Rhamnus
Author(s): Marshall C. Johnston and LaVerne A. Johnston
Source: Flora Neotropica, Vol. 20, Rhamnus (Dec. 18, 1978), pp. 1-96
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RHAMNUS by
Marshall C. Johnston and LaVerne A. Johnston
NEOTROPICA/
TSOPic
o
CAPOICOUN
-pX.-x.
Publishedfor
Organization for Flora Neotropica by
The New York Botanical Garden New York
December 18, 1978
All material subject to this copyright appearing in Flora Neotropica may be photo- copied for the noncommercial purpose of scientific or educational advancement.
Published by
The New York Botanical Garden Bronx, New York 10458
International Standard Serial Number 0071-5 794 International Standard Book Number 089327-209-4
Library of Congress Cataloging in Publication Data
Johnston, Marshall Conring, 1930- Rhamnus.
(Flora neotropica ; monograph no. 20) Bibliography: p.
Includes index.
1. Buckthorn. 2. Botany--Latin America.
I. Johnston, LaVerne A., 1930- joint author.
II. Organization for Flora Neotropica. III. Title.
IV. Series.
QK495.R45J63 583'.279 78-16036
ISBN 0-89327-2C9-4
Rhamnus Linnaeus,one of the three genera of Rhamnaceae in which each of the fleshy fruits contains two or more free stones (Johnston, 1974), com- prises more than 125 species. We usually think of Rhamnus in terms of north- temperate shrubs, but members of the genus are well represented in the Old World tropics and slightly less well in the Neotropics, where we find shrubs and small trees and even trees "five feet DBH and 150 to 200 feet tall" (D. E.
Breedlove, in litt. 9 October 1976). Although the temperate-zone species, especially the European ones, are relatively well known and understood taxonomically, those of the tropics have been neglected.
The two most important systematic treatments of the American species of Rhamnus sensu latiore published in the last 40 years both suffer from a provincial outlook perhaps even more severely than do most monographic works. C. B. Wolf's (1938) revision of the North American including Mexican and West Indian taxa is careful and thorough as to the species of the United States and Canada and especially as to the Californian taxa, with which the author was familiar in the field, but his treatment of the Mexican and West In- dian taxa bespeaks more haste than understanding. He misused at least one name as a consequence of failure to examine the type, and confused under one name two common tropical Mexican species.
The publication 11 years later of a world-wide revision (V. I. Grubov, 1949), based almost solely on materials in the Leningrad herbarium, failed to improve the situation. Although his treatment of the species of Europe and western Asia has apparently stood the test of time, Grubov's detailed in- frageneric system, replete with 10 sections and 54 series, was less successful.
And the revision of the tropical American species can best be described as only partially convincing. Some American taxa, including species proposed by Wolf, were left untreated in the absence of material for study. Others were treated only on the basis of published data without first-hand study of collec- tions; and a number of poorly characterized species were proposed on the basis of solitary specimens. The Russian work has languished in well deserved ob- scurity while for decades the herbarium-stores accumulated in appalling disarray, with the South American plants in particular passing under assorted later homonyms. In view of this disorder, and the proposals in recent years of several new tropical American species, it appears that the time is over-ripe for the publication of a new treatment. This paper presents a system for the plants of tropical America.
Department of Botany, The University of Texas at Austin, Austin, Texas 78712.
1
HISTORY
Only three genera of rhamnaceous plants were recognized by Linnaeus (1753, 17.54): Rhamnus included plants with indehiscent, more or less drupaceous fruits; Ceanothus Linnaeus included those with superior ovaries maturing into capsules; and Phylica Linnaeus those with inferior ovaries maturing into capsules. Miller (1754), perhaps the first author to reassert the validity of genera recognized by Tournefort and other pre-Linnaean authors, again segregated from Rhamnus the Alaternus P. Miller, Frangula P. Miller, Paliurus P. Miller and Ziziphus P. Miller. For the rest of the eighteenth cen- tury and the early decades of the nineteenth no consensus existed as to the cir- cumscription of these taxa and related ones being discovered; some authors adopted the inclusive Linnaean taxa, others the Millerian segregates, or various combinations of them.
The modern concept of the family and circumscription of its genera date only from the masterful inaugural dissertation of A. Brongniart (1826). All subsequent over-all systems for the family, up to and including the latest, that of Suessenguth (1953), are lineal descendents of the careful, intelligent work of Brongniart. The plants in which each mature, indehiscent fruit has two or three or rarely four free uniovulate stones are treated in three genera, Rham- nus, Sageretia A. Brongniart and Scutia A. Brongniart, just as they still are (Johnston, 1974). Brongniart's Rhamnus includes, as recognized infrageneric taxa, Miller's Alaternus and Frangula.
Thoughl there has been no further controversy with respect to Alaternus, which remains a section of Rhamnus, the question of whether Rhamnus should also include Frangula is moot. It was answered affirmatively in the last century and a half by almost all workers including de Candolle (1825), En- dlicher (1840), Steudel (1841), Bentham and Hooker (1862), Weberbauer (1895), Suessenguth (1953) and almost all American and European flora- writers.
Those at least temporarily on the other side of the question include A.
Gray (1849), Grisebach (1859) and Reissek (1861). A trend in this century to re- open the issue dates from the anatomical survey of rhamnaceous leaves by two of Radlkofer's students in Munich (Gemoll, 1903, Herzog, 1903) who showed that all Frangula leaves differ from other species of Rhamnus including Alater- nus. The work of Heppeler (1928) on the fruits and seeds turned up other con- stant morphological differences between Frangula and the rest of Rhamnus.
Enlarging upon Heppeler's work, Grubov (1949a) thoroughly studied Rhamnus insofar as material was available at Leningrad. He confirmed the constancy of the seed and fruit differences between Frangula and the rest of Rhamnus, and he cited other workers to the effect that the vessels have a dif- ferent distribution in the xylem of Frangula than in that of the rest of Rham- nus. Evoking for support the ghosts of "Gray, Bennett, Reichenbach, Grisebach and others" he elevated Frangula once again to generic rank. The generic segregation of Frangula by Grubov (1949a, 1949b) has been followed by Tutin et al (1968) and Davis and Yaltirik (1967). This tendency to recognize segregate genera seems to be fashionable in Europe. With regard to Rhamnus it was carried to an extreme by Vent (1962) who elevated another section of
That Frangula is a natural probably monophyletic group is unquestioned. Also unquestioned is that it is exceedingly closely related to Rhamnus, more closely in fact than either group is to other taxa of the family.
The hierarchic rank at which these relationships are to be recognized is not a scientific question but one depending on tradition, usage and the practical consideration of the optimization of communication. M. C. Johnston (1975) called attention to this in connection with the proposed segregation of Chamaesyce S. F. Gray from Euphorbia Linnaeus. In particular in groups like Rhamnus and Euphorbia that have some economic importance and that are well known and recognized under those names not only by hundreds of systematic botanists but by legions more of field ecologists, phar- macognocists, agriculturists, forestry managers, etc, it ill behooves us to in- dulge in capricious changes of hierarchic rank that are not based on clear evidence of polyphylesis. The result is to make less accessible and less com- municable an already formidably esoteric body of knowledge. Of the 21 species recognized in this paper, 20 pertain to Frangula, but until Grubov's paper only a handful had been provided with binomials in the "genus"
Frangula. Several are of considerable economic importance. Surely the bee- busy taxonomic fraternity can admit the existence of well marked subgenera that do not require elevation in rank, regardless of current fashion.
MORPHOLOGY
Plants of the genus Rhamnus are relatively unspecialized shrubs or trees, rarely (never in our species) with a tendency to sprawl or climb. The American ones are never spiny or thorny. The phyllotaxy in our species is spiral, ap- proaching opposite only in R. granulosa (Ruiz & Pavon) Weberbauer. Each simple leaf has two, small, free, usually caducous stipules. The venation is of an ordinary pinnate type with the secondary veins describing gentle arcs to near the margins. The margins are usually toothed. The pubescence ranges from nearly absent to very dense, and the hairs are simple, never forming truly stellate assemblages, though rarely a few emerge close together to form a bun- dle.
The inconspicuous flowers are borne in small axillary cymose aggregations; the cyme is rarely reduced to a single flower. As is true for the family as a whole, a tiny floral cup is present, at the rim of which are borne the four or five minute, deltoid sepals, valvate in bud. In all of our species, minute, thin, white or greenish white petals occur between the sepals; they are more or less clawed, and the expanded distal portions are concavo-convex and at early stages form hoods over the stamens or staminodes which are of the same number and opposite them. The floral cup is lined with a relatively thin nectariferous tissue. The minute ovary represents two or three joined carpels and has two or three locules. At the base of each locule is attached the solitary, erect, anatropous, bitegmic ovule. Maturation requires several weeks
or even months. At maturity the fruit is drupaceous but unlike drupes, as usually defined, the pulpy mesocarp embeds not one but two or three free one- seeded stones (for terminology see Brizicky, 1964). The cartilaginous en- docarp thus undergoes an internal schizocarpy, as it were, considered to be an evolutionary hold-over from a truly schizocarpous or colubrinoid dehiscence (Johnston, 1971). The endosperm contains much lipid material and very little if any starch.
Only a few species, none of them neotropical, have been studied em- bryologically (Davis, 1966). Similarly, we have been unable to find any published chromosomal or cytological information on neotropical species of Rhamnus.
Anatomical details have been reported for the leaves of only six neotropical species of Rhamnus (Herzog, 1903), including R. serrata Schultes of Rhamnus subgenus Rhamnus, and five species of Rhamnus subgenus Frangula (Miller) Dippel. Herzog describes the leaves of all these species as bifacial and the cuticle as smooth except in R. microphylla Schultes in which it is extremely finely striate. Crystal-druses of calcium oxalate are reported in all, especially near the veins. The presence of mucilage-receptacles in subgenus Frangula and their absence in subgenus Rhamnus including R. serrata is repor- ted. It is reported that Frangula as a whole, including four of the neotropical species, exhibits multicellular hairs; the fifth species R. microphylla being glabrous. We examined partially cleared leaves of the same neotropical taxa (but not the same collection) and find exclusively unicellular hairs. Rhamnus serrata, reported to be glabrous, as a member of subgenus Rhamnus would be expected to have unicellular hairs, if any. Rhamnus microphylla is reported to be distinctive also on account of its one-layered palisade, versus two- or three- layered in the rest, and the fact that even its larger veins are embedded in mesophyll tissue.
The anatomical distinctiveness of R. microphylla seems at first glance to be of taxonomic utility. Unfortunately, the identity of the voucher specimen, destroyed at Berlin-Dahlem in 1943, is thrown into doubt by its citation as having been collected by Bertero in Santo Domingo, a locality in which the Mexican R. microphylla is not known to occur. Thus we cannot take the data at face value.
For ease of reference we list below the neotropical taxa studied by Her- zog, and parenthetically the voucher collection with our present determination:
Rhatminus serrata Schultes (Pringle 8055, correct), R. "capreaefolia"
Schlechtendal ("Donnell Smith " = Heyde et Lux 3051, referred to a variety of R. capraeifolia), R. microphylla Schultes (Bertero s n, identity unknown), R.
sphaerosperma Swartz (Sintensis s n, correct), R. "sectipetala" Martius ex Reissek (Widgren s n, referred to a variety of R. sphaerosperma), and R.
palmeri Watson (Pringle 4427, correct). It should be noted that Herzog took his leaf-fragments from subsequently destroyed specimens at Berlin-Dahlem, and that the determinations listed above are based on examination of presumed duplicates at other herbaria bearing the same label-data. A cloud of doubt is thrown over all the anatomical data in view of the discrepancies in Herzog's and our observations on the structure of the hairs.
The macroscopic differences between Rhamnus subgenera Rhamnus and
Frangula, the general conditions are compared with those found in the 20 neotropical species. The general conditions in Rhamnus are compared with those in R. serrata, the sole neotropical member.
SUBGENUS FRANGULA SUBGENUS RHAMNUS
1. Inflorescences simple or compound false- 1. Inflorescences mostly fasciculate, rarely umbels, ie pleiochasia, rarely fasciculate. racemose or paniculate, but never umbel-like.
(Neotropical species: correct, less commonly (R. serrata: flowers solitary or usually in flowers solitary). fascicles of 2 or 3 (to 5); theoretical distin- ction between small pleiochasium and reduced cymose inflorescence not clear).
2. Flowers always bisexual, 5-merous. 2. Flowers predominantly unisexual, (Correct, a few flowers often 4-merous on dioecious, rarely bisexual or polygamous,
same plant). merosity not specified. (R. serrata: probably
unisexual and dioecious; see L. A. Johnston, 1975).
3. Sepals fleshy, erect, keeled ventrally. 3. Sepals thinner, spreading, unkeeled. (R.
(More or less correct, sepals often slightly serrata: sepals obscurely keeled, ascending).
spreading).
4. Petals always well developed, short and 4. Petals usually small, lanceolate, often broad, abruptly tapering into a short and (mainly in the pistillate flower) absent or very narrow claw, emarginate at tip. reduced. (Correct).
(Correct).
5. Stamens always well developed with large 5. Stamens with small anthers on thin, long anthers on short filaments almost as long as filaments, in the pistillate flowers usually anthers. (Ambiguous, not clearly different.) reduced to staminodes. (Ambiguous, not
clearly different.)
6. Style straight, simple; stigma capitate, 6. Style 2-3-4-parted; lobes spreading. (R.
trifid. (Correct). serrata: not apparently different from other neotropical species.)
7. Ovary always 3-locular. (Some species 7. Ovary 2-3-4-locular, in the staminate with almost constantly 2-locular ovaries, flowers always completely absent. (R.
most with constantly 3-locular ones). serrata: ovary constantly 2-locular).
8. Stones 3 or by abortion rarely 2. (Correct, 8. Stones 2-3-4. (R. serrata: 2).
but in a few species 2 stones more common than 3; it is to be noted that the type species, R. frangula of Europe, has almost constantly 2-stoned fruit.)
9. Stones remaining intact, lenticular. 9. Stones splitting open within the fruit at
(Correct). mid-ventral suture. (R. serrata: correct).
10. Seeds lenticular, unfurrowed; testa with 10. Seeds oval or ovate, with dorsal or lateral horn-shaped thickening at lower end that furrow, rarely flat and unfurrowed, com- protrudes from the opening in the endocarp pletely enclosed in endocarp. (R. serrata:
in the shape of a beak-like rostellum. correct).
(Correct).
11. Cotyledons thickened, each flat and both 11. Cotyledons thinner, folded along the in one plane, slightly convex, straight. furrow, rarely straight, (R. serrata: not ap-
(Correct). parently thinner than in Frangula, main axis
of embryo and midveins of cotyledons in a straight line, lateral parts of both cotyledons arching away from the plane between the stones).
12. Buds naked, without protective scales. 12. Buds with protective scales. (Correct).
(Correct).
13. Lateral veins of leaves straigth or slightly 13. Lateral veins of leaves mostly curved, not curved, parallel. (Secondary veins describing parallel. (R. serrata: secondary veins arcs to near margins). describing arcs to near margins).
14. Leaves and branches always alternate. 14. Leaves and branches opposite or later-
(Correct). nate. (R. serrata: alternate).
15. Twigs never spinescent. (Correct). 15. Twigs often transformed into thorns. (R.
serrata: wholly unarmed).
POLLEN
The neotropical species of Rhamnus are unknown palynologically, in spite of the recent expansion of our knowledge of the family by Papagiannes (1974).
CHEMISTRY
The chemistry of neotropical species of Rhamnus has not been in- vestigated (Hegnauer, 1974).
POLLINATION AND DISPERSAL
We have observed various small bees and flies working the flowers of R.
serrata and R. capraeifolia in Mexico; we have no precise determinations of the kinds of insect nor any information on the extent to which they may truly have been effecting pollination of the flowers. The presence of petals and of nectariferous tissue in all neotropical species supports the contention that all are pollinated through the mediation of insects. We have been unable to find any other information applying to the pollination of neotropical Rhamnus species.
Fleshy fruits are generally considered to be part of a syndrome of features associated with seed-dispersal by animals. The drupaceous fruits of Rhamnus have been considered more specifically to be adapted to bird- dispersal (Stebbins, 1974), though this notion is not backed up by any eviden- ce, particularly with respect to neotropical species. Martin et al (1951) list a number of kinds of birds said to consume the fruits of temperate North American Rhamnus. Mental extrapolation of this kind of bird-plant relation to neotropical areas is plausible. The fruits of some temperate kinds of Rh- amnus contain substances toxic to humans (Hegnauer, 1974; Lewis and Elvin- Lewis, 1977), and it seems plausible to predict similar toxicity of neotropical Rhamnus fruits. It is interesting to speculate that a variety of birds may have the physiological mechanisms to detoxicate ingested Rhamnus fruits. One of the human physiological effects of ingestion of temperate Rhamnus fruits is violent purgation (Lewis and Elvin-Lewis, 1977). Perhaps a similar effect in
DISTRIBUTION
Tropical America is not uniformly supplied with Rhamnus species.
Coastal plains, the Yucatan penninsula and Amazonia (Fig 20) are devoid of Rhamni. The only possible exceptions are the few populations straying fairly close to the Atlantic coast in southern Brazil, but even these are not truly inhabitants of hot lowland formations. Even in extratropical southern Brazil, Rhamnus avoids the warm coastal lowlands (Johnston and Soares, 1972).
The densest massing of species is in the highlands of central and southern Mexico (Figs 3, 5, 10, 15) and the next densest in Central America and the Greater Antilles (Fig 8). The South American continent (Fig 20) is thinly spread over a gigantic C-shaped arc from Venezuela to Brazil, with a con- siderable hiatus only in the chaco of Paraguay and extreme southeastern Bolivia.
ECOLOGY
It is to be hoped that under such a heading as "ecology" one may read about the precise habitat requirements of neotropical Rhamnus plants as determined by autecological experiment as well as detailed information on the dynamics of vegetational communities of which Rhamnus is a part. Since this information is unavailable, we offer only a few generalities on the sorts of habitats and vegetational communities from which neotropical Rhamnus plan- ts have been collected.
The most salient fact seems to be the avoidance by the genus of hot tropical lowlands, either those that are forested or those in which grassland, savannah or "chaco" vegetation predominates. The preferred habitat has a relatively mild upland or montane climate in areas with sufficient moisture to support a forest or at least a tall scrubby growth. In central and southern Mex- ico, Central America and the Antilles Rhamnus is most commonly associated with montane woodland made up at least partly of oak, Quercus Linnaeus, and often with pine, Pinus Linnaeus. In southeastern Brazil the margins of thickets in the upland campos and areas where members of the genus Araucaria Jussieu abound are preferred. A few species of Mexico and Central America appear to prefer montane "cloud forests" where the light in- tensity is very low and the humidity rarely drops below a level of saturation of atmosphere and substrate. Some seem to occur in forests with sufficient rain fall to qualify as true rainforest, but most are in areas of rainfall averaging 90 to 150 cm per year. The limit of xerophytism of the neotropical species is probably found in the Mexican R. microphylla, and even it inhabits only moderately dry intermontane areas with annual rainfall from 70 to 100 cm per
year. Neotropical Rhamnus species have not been found in any truly desertic formation.
SYSTEMATIC POSITION OF NEOTROPICAL MEMBERS Rhamnus serrata, our only representative of the nominate subgenus, is placed by Grubov (1949) in a unispecific series between two bispecific series comprising temperate North American species. These three series as shown below constitute one section of the total of six sections into which Grubov divides the subgenus. It seems inadvisable here to perpetuate Grubov's names;
they were never validated by Latin diagnoses and it seems premature to propose a different over-all system.
Series 1. (R. lanceolata Pursh; R. smithii Greene) Series 2. (R. serrata Schultes)
Series 3. (R. crocea Nuttall; R. insularis Greene)
We agree that these five American taxa are closely related. Grubov follows Wolf (1938) in stating that R. serrata has an evergreen habit as opposed to the deciduous habit of Series 1, but L. A. Johnston (1975) corrected this im- pression; at this point we see no basis for distinguishing Series 1 and Series 2.
The Series 3 is somewhat more distinctive, but exhibits more specialized characters than the other three species and cannot be considered basal to the group. Of the three closely related species R. lanceolata, R. smithii and R.
serrata, none seems more primitive than another, and they appear to be products or relics of trivial regional genetic differentation in a previously even more widespread complex. They are not at all closely related to the only other American species of the subgenus, the sub-boreal R. alnifolia L'Heritier. We have been unable clearly to connect them to any species of the Old World, where the overwhelming bulk of the subgenus is arrayed. They remain phyletic and taxonomic orphans.
Rhamnus subgenus Frangula, to which 20 of our 21 species pertain, was divided by Grubov (1949, under the "genus" Frangula) into three sections, as follows (again, suppressing his invalid names).
Section I. European species, including the type species.
Section II. Inflorescence a complex, branched, many-flowered false umbel on well developed peduncle; young branches, inflores- cences and the leaves beneath along veins with appressed pubes- cence or glabrous; leaves dentate with straight, numerous parallel veins that are connected by lateral veins.
Subsection I. Including four series of Asiatic species.
Subsection II. Temperate North American species plus the neotropical Mexican R. microphylla and R. stenophylla Standley. Semi-umbels many-flowered on small peduncles,
without foliaceous bracts.
pilose to densely tomentose. All other neotropical species, ar- ranged in two subsections, the first with seven series and the second with three series.
Subsection I. Young branches, buds, petioles and main veins of leaves rust-colored or brown-pubescent; leaves at tip acute or with narrow cusps; ovary strigose-pubescent. All South American, Antillean and some Central American species. The seven "series" are based on size, texture and pubescence of leaves, number of veins and details of in- florescence.
Subsection II. Semi-umbels on short peduncles or sessile, simple; ovary glabrous; young branches, pedicels and veins grayish or yellowish short-pubescent or glabrous; mostly shrubs. All tropical Mexican and some Central American species plus one temperate north-Mexican species. The three series are based on shape, size, texture and pubes- cence of leaves and details of inflorescence.
Without examining all details of Grubov's subsectional and serial system, we may perhaps indicate the extent to which we differ from and reject his system by stating that we include in one species plants that he refers to six dif- ferent series. We consider one species in his first series to be conspecific with one in his fourth series. We condense his 25 species of neotropical Rhamnus subgenus Frangula into only 12 species, some with varieties. (We treat eight more species not included at all by Grubov.) Grubov's recognition of
"species" based for the most part on solitary specimens fails utterly to take in- to account the variability that is inherent in Rhamnus populations and that becomes most apparent upon study of much material collected in the last 25 years. To end on a positive note, although we do not consider that the charac- ters that he mentions to distinguish his two final subsections really hold up, we concede that all the species of his first subsection are truly distinct from all those in his second.
Although we do not believe that the one previously proposed system truly reflects natural relationships among neotropical species of Rhamnus subgenus Frangula, we are at a loss to suggest an alternative. We do not per- ceive morphic discontinuities sufficiently great to permit recognition of species groups or series. The neotropical species seem to form a phyletic unit that is fairly compact, not in geographic parameters but in terms of the over-all diversity which consists largely of new recombinations of apparently trivial traits. It is to be hoped that future acquisition of anatomical, ultrastructural, cytological and chemical data, etc, may point clearly toward species-groupings, but the matter is unresolved at present.
If pressed for speculation on the overall position of the neotropical
species of this subgenus, we would have to make the generalization that they are most closely related to the temperate North American species and that the New World species as a group find their closest relatives among the Asiatic species. That leaves the few European species as the most distant relatives.
Key to the Species of Rhamnus
1. Bud-scales present; flowers 4-merous. 1. R. serrata.
1. Bud-scales absent; flowers 5-merous.
2. Branches short, straight, stiff and stout; petioles 1.0-2.0 mm long; leaves rarely exceeding 2.2 cm long, 0.2-0.7 cm wide; ovary 2 celled; fruits 2-seeded; Mexican states of San Luis Potosi,Aguascalientes,Nayarit, Hidalgo, Guanajuato, Jaliseo
and Tlaxcala. 4. R. microphylla.
2. Branches not as above; petioles very rarely less than 2.0 mm long; leaves generally larger than above; ovary 3-celled; fruits 3-seeded or if 2-seeded usually with a third abortive carpel.
3. Leaves with margin strongly and conspicuously revolute and tertiary venation above deeply impressed; external floral parts red and pilose; high mountains
of Columbia and Venezuela. 16. R. goudotiana.
3. Leaves with margins either plane or if revolute not strongly or conspicuously so; external floral parts not red.
4. Leaves beneath with short, dense tomentum, almost always on some part of plant the hairs arising in groups of two or more from a single point.
5. Stipules up to 6 per node and, at base of pedicels, persistent; leaves rarely exceeding 8.0 cm long and mostly lanceolate; leaf above usually tomen-
tose; tropical Mexico only in Jalisco. 3. R. scopulorum.
5. Stipules quickly deciduous; leaves often exceeding 8 cm long and mostly elliptic; leaf above from glabrous to moderately hairy; fruits only rarely glabrous; Mexican state of Chiapas, Socorro Island, Guatemala, Costa
Rica and Panama. 18. R. sharpii.
4. Leaves beneath with hairs either longer or sparser, none arising in groups from a single point.
6. Leaves 1.3-2.0 times as long as wide, above and beneath with more or less dense, long, coarse pubescence, margin always plane with teeth mainly obscured by hairs.
7. Leaves 3.2-8.0(-9.2) cm long, (1.9-)2.1-5.0(-6.3) cm wide, above and beneath with dense pubescence; peduncles rarely absent; pedicels in fruits rarely longer and usually shorter than 10 mm; usually more than 5 flowers and up to 6 fruits per axil; Mexican states of Jalisco,
Michoacan and Mdxico. 6. R. palmeri.
7. Leaves smaller, 1.4-4.7(-5.3) cm long, 0.8-2.4(-3.3) cm wide, above and beneath pubescence only moderately dense; peduncles absent;
pedicels in fr usually longer than 10 mm; rarely more than 5 flowers and one fruit (or occasionally up to 3) per axil; Mexican states of
of Guerrero, Oaxaca, Chiapas and into Central America. 7. R. pringlei.
6. Leaves not usually so wide in proportion to length with pubescence shorter or less dense and marginal teeth more readily apparent.
8. Leaves rarely up to 8 cm, usually a maximum of 4.0-5.5 cm long;
stipules persistent.
9. Leaf-bases acute or obtuse; fruits 10-11 mm in diam; Jalisco and
Michoacan. 5. R. macrocarpa.
9. Leaf-bases cuneate to rounded or sometimes oblique; fruits rarely exceeding 7 mm in diam.
10. Leaves rarely exceeding 3.5 cm long; fruits mostly 2-seeded;
1900-2500 m alt; Durango and Zacatecas. 2. R. rosei.
rarely shorter than 9 mm and up to 15 mm; floral cup in fruit with entire margin; Veracruz, Hidalgo, Puebla, Oaxaca.
13. R. mcvaughii.
11. Venation above with coppery overtones but not dark;
pedicels in fruits 6-7(-8) mm long; floral cup in fruit angular (pentagonal, stellate) with a tendency for floral parts to persist; Chiapas, Mexico and Huehuetenango, Guatemala.
14. R. breedlovei.
8. Always some (or even all) leaves longer than 5.5 cm; stipules persistent or quickly deciduous.
12. Stipules persistent; leaves up to almost 4 times as long as wide;
floral cups ca 0.7 mm long, 1.5 mm broad; from central Venezuela
(state of Bolivar) eastward. 19. R. ulei.
12. Stipules persistent or not; leaves rarely more than 3 times as long as wide; floral cups at anthesis larger.
13. Each marginal tooth of leaf with a rather long, blunt mucro;
peduncles absent; flowers broad and shallow, floral cups usually 2 mm deep and rarely less than 3 mm broad (up to 4 mm); ovaries and fruits glabrous, floral parts retained in fruit;
high mountains, Costa Rica. 15. R. oreodendron.
13. Each marginal tooth with mucro shorter or absent; flowers large or small but if large then not so broad and shallow, with floral cup rarely more than 3 mm broad; ovaries and fruits glabrous or pubescent; floral parts persistent or not.
14. Branchlets tending to be and sometimes opposite, stout and often thickly beset with wart-like lenticels; leaves mostly 6-9 cm long; peduncles present; floral cup as broad as long; sepals wider than long; ovary and fruit hairy;
Colombia, Peru and Ecuador. 20. R. granulosa.
14. Branchlets more definitely alternate and without wart- like lenticels; leaves of variable lengths; peduncles present or absent, ovary and fruit hairy or not; floral cup broader than deep or if breadth and depth subequal then peduncles absent; sepals ca as long as or longer than wide.
15. Leaves mostly 1.9-8.5 cm long (rarely longer); petioles (2-)4-9(-13) mm long; ovaries and fruits glabrous:
fruits mostly 7-8 mm in diam; an otherwise and rather widespread species from central and western Mexico
southward into Guatemala and El Salvador. 12. R. mucronata.
15. Leaves larger on the average or if as small then petioles averaging or actually longer; ovaries and fruits glabrous or hairy; fruits averaging or actually smaller in most cases.
16. Leaves mostly 5.0-8.5 cm long; entire plant pale- ly crisply villous (i e, hairs erect but seldom straight, rather irregular in configuration, not matted, up to 0.3 mm long); leaves only rarely glabrous above and with moderate amount of hair beneath; leaf surfaces concolorous; flowers 3-12 (-14) per axil; peduncles absent; sepals ca 1.0 mm long (rarely to 1.5) and usually ca as wide; floral cup rarely deeper than 1.0 mm; petals mostly 0.6- 0.8 mm long; Veracruz, Hidalgo, Puebla and Oaxaca.
9. R. pompana.
16. Leaves often longer; plant usually not crisply vil- lous; leaves glabrous or not above or beneath, be- neath paler than above usually; if peduncles absent then flowers usually fewer per axil; sepals and petals longer.
17. Stipules 3.0-4.0 mm long; leaves (3.0-)4.0-6.0 (-8.0) cm long; larger veins beneath glabrous or sparsely antrorse-appressed pubescent;
flowers 1-2 per axil; pedicels in flower 6.0-8.0 mm long; floral cup ca 2.0 mm deep and ca as broad; sepals 2.0-2.5 mm long and ca as wide;
pedicels in fruit 10-13 mm long or longer;
Venezuela, Prov. Truxillo and Puerto Cabello
only. 21. R. lindeniana.
17. Stipules usually shorter or averaging shorter;
leaves longer or averaging longer; venation be- neath usually with more hair; flowers usually more numerous; pedicels in flower shorter or longer; floral cup broader than deep; sepals usually smaller but if as large then longer than wide; pedicels in fruit usually shorter.
18. Leaf-margin conspicuously serrate or cre- nate; sepals and floral cup 2.0 mm long or longer; pedicels in flower (5.0-)9.0-13.0 mm long; petal enclosing no more than 2/3 of anther; petals 1.5 mm long; anther 1 mm long; fruit usually 1 per axil.
10. R. longistyla.
18. Leaf-margin usually somewhat remotely toothed but if conspicuously so then teeth generally irregular in size and shape; sepals and floral cup up to 2 mm long; pedicels in flower shorter; petal smaller but en- closing more of anther; anthers shorter;
fruits often more numerous.
19. Leaf-margin always plane, conspicu- ously serrate or dentate, the teeth irregular in size and shape; flowers mostly 3 and fruits 1-3 per axil; ped- icels in fruit 6-11 mm long; fruits 6-8 mm in diam; Mexican states of Jalis- co, Michoacan, Guerrero, Mexico and
Morelos. 11. R. hintonii.
19. Leaf-margins both plane and revolute, serrate or crenate but if conspicuously so then teeth not so irregular; flowers and fruits usually more numerous;
pedicels in fruit either actually or averaging shorter; fruits often averag- ing somewhat smaller.
20. Leaves either with pustules or smaller veins above or conspciu- ously dense pubescence on major veins beneath especially at juncture of midvein and secondary veins;
eastern Mexico to Guatemala, El
Salvador, Costa Rica. 8. R. capraeifolia.
to Hispaniola, southern Mexico.
17. R. sphaerosperma.
1. Rhamnus serrata Humboldt & Bonpland ex Schultes in Roemer and Schultes, Syst. 5:295. 1819.
Shrubs 0.3-3.0(-5) m tall, deciduous or evergreen. Bark variable in color with usually a moderate amount of mostly straight and erect short to long hairs. Branchlets (0.6-)0.9-9.5(-16.0) cm long with leaves not very crowded.
Bud scales 1-2 mm long, coriaceous, dark-colored, with marginal or dorsal hairs, and with apex broadly obtuse and occasionally notched. Stipules 2.0- 5.0(-6.0) mm long and ca 0.5 mm wide, thin or moderately thick, pale-colored, and with sparse to moderate amounts of hairs which are scattered or ex- clusively on the margin or midvein, quickly deciduous or persistent; petioles 1.0-4.0(-5.0) mm long with moderate to dense amounts of short to moderately long hairs which may be confined to or concentrated on a ventral furrow; leaf blades (0.3-)0.5-4.2(-8.4) cm long and (0.1-)0.4-1.5(-2.0) cm wide, from broadly elliptical and ovate to oblong and lanceolate, from thin and flexible to firm and moderately thick; apex acute or obtuse or occasionally acuminate or retuse; margin revolute or plane, serrate or crenate, teeth with mucros pale to dark in color and from large to small or absent; above either actually or ap- parently glabrous, the short erect hairs usually visible only if leaf-surface is at an angle to the lens, beneath yellowish to brownish or the same color as above or occasionally simply paler green than above and either glabrous or with short erect hairs; venation above inconspicuous or conspicuously pallid and either glabrous or with midvein usually hairy and secondaries with the same amount of hair or less or sometimes glabrous, hairs erect and of variable lengths.
Flowers associated with mature leaves, 1-3 (rarely 4 or 5) per axil; peduncles absent; pedicels usually 3 mm long or shorter (rarely up to 6 mm); flowers monoecious or polygamodioecious or protandrous, 4-merous; floral cups varying in shape from funnelform through urceolate and campanulate to hemispheric (the latter uncommon), (0.6-)1.0-1.5(-2.0) mm deep (usually shallower in 9 than in cr flowers), 1.0-2.0 mm broad, usually broader than deep glabrous or with sparse to moderately sparse short, erect pubescence;
sepals 1.0-2.0 mm long, 0.6-1.5 mm wide (usually smaller in 9 than in or flowers), glabrous or with sparse to moderate pubescence; petals 0.5-1.1 mm long (shorter in 9 flower), enclosed by petal partially in oc flower and completely in 9 flower. Fruits 1-2 per axil; pedicels (1.5-)2-4(-6) mm long; floral cup with petal, uniformly colored or with the distal portion darker; anther 0.5-0.75 mm long (shorter in flower), enclosed by petal partially in cr flower and completely in 9 flower. Fruits 1-2 per axil; pedicels (1.5-)2-4(-6) mm long; floral cup with margin entire or notched on two sides and glabrous or with short hairs; drupe (3.0)4.0-6.0(-8.0) mm broad, either globose or somewhat prolate, glabrous, 2- seeded (rarely 3-seeded); style retained or not, stigma bifurcate or trifurcate.
Distribution (Fig 3). In the USA from Arizona through New Mexico and western Texas into the Mexican states of Chihuahua, Coahuila, Nuevo Leon and Tamaulipas southward through central Mexico and into the Guatemalan province of Huehuetenango. In mountainous areas mostly on slopes or in canyons but also on peaks and ridges with substrate mostly limestone but also igneous rock and occasionally gypseous or rhyolitic rock varying in texture from fine loamy through gravelly to rocky, in either open or dense woods, forests, or brushy or scrubby areas in association most frequently with oaks and less frequently with pines, junipers, fir, and sotol in that order (also grass, Nolina, Ptelea, Garrya, Juglans, Yucca, Pseudotsuga, Acer, Alnus, Fraxinus, and "palo loco").
Key to Varieties of Rhamnus serrata
1. Stipules quickly deciduous or somewhat persistent but only rarely at leafless nodes, averaging more than 3 mm long; Arizona, southern New Mexico, western Texas southward through central Mexico into Chiapas, alt less than 3000 m.
la. var serrata.
1. Stipules abundant, persistent even at leafless nodes, averaging less than 3 mm
long; Huehuetenango, Guatemala, above 3000 m alt. lb. var guatemalensis.
la. Rhamnus serrata Schultes var serrata Fig 1.
Rhamnus serrulata Humboldt, Bonpland & Kunth, Nov. Gen. et Sp. 7: 51. t. 617. 1825. (as synonym of Rhamnusserrata), nomen superfluum.
Rhamnus fasciculata Greene, Leaflets Bot. Obs. 1: 63. 1904. (Type. Wooton 203, USA, New Mexico, White Mountains, 25 Jul 1897, POM, US.)
Rhamnus smithii subsp fasciculata (Greene) Wolf, Monogr. Rancho Santa Ana Bot. Gard.
Bot. Ser. 1: 58. 1938.
Rhamnus smithii subsp fasciculata var mulleri Fosberg, Lloydia 4: 286. 1941. (Type.
Muller 3188, Mexico, Coahuila, Sierra de la Madera, Mun. de Cuatro Cienegas, Caion del Pajarito, rare in moist oak-maple forest, 6 Sep 1939, NA.)
Shrub 1-3(-5) m tall, deciduous or evergreen; bark greenish or when young reddish, grayish, or brownish when older with hairs short to long (long only in Texas and most Coahuila collections), mostly erect and straight, of usually moderate amount, sometimes glabrate with age. Branchlets (0.6-)0.9- 9.5(-12) cm long (averaging ca 1.0-2.5 cm), with (4-)6-8(-14) leaves per bran- chlet. Bud-scales dark reddish in color, apex broadly obtuse, hairs dorsal nor- th of the tropics and marginal only in the tropics. Stipules 2.0-5.0(-6.0) mm long, usually pale reddish, either thin or moderately thick with hairs often ex- clusively on the margin or midvein, either quickly deciduous or somewhat persistent (rarely at leafless nodes). Petioles 1-4(-5) mm long with moderate amounts of short to moderately long hairs which may be confined to or con- centrated on a ventral furrow. Leaf-blades (0.3-)0.5-4.0(-8.4) cm long with the shorter leaves usually proximal on the longer branchlets or throughout the shorter branchlets, usually the smaller leaves broadly elliptic or ovate and the larger leaves oblong or lanceolate; thin and flexible to firm and moderately
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FIG I. Rhamnus serrata var serrata (Rzedowski 27245, TEX). The vertical line long.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~?:i: is 5 cm
thick; base cuneate to rounded, apex mostly acute or obtuse (some apexes acuminate in the Chiapas collection, some retuse in a few collections from far- ther north), margins revolute more commonly in the southern part and plane more commonly in the northern part of the range, usually serrate but sometimes crenate with (6-)10-15(-17) teeth per cm having apexes all colorless or amber-colored or dark and sometimes prominently large; above green, beneath yellowish to brownish (simply paler green in a few New Mexico collec- tions) and either apparently or actually glabrous or with moderate amounts of usually short, erect hairs; secondary venation only rarely glabrous. Flowers with petals either uniformly colored or with distal portion darker. Fruiting pedicels (1.5-)2.0-4.0(-6.0) mm long and with usually moderate pubescence, style sometimes retained, fruits 2-seeded.
Type. Humboldt & Bonplands n (B-WILLD No. 4637), Mexico.
Distribution (Fig 3). In the U S A in Arizona, southern New Mexico, and western Texas and throughout central Mexico. From 1200-2900(-3000) m alt (mostly 2000-2200). Flowering from January through the third week of June;
fruit beginning in May.
UNITED STATES. Arizona: Hevly sn (ARIZ); White Mountains, fl, summer 1938, Schroeder s n (ARIZ); Chiricahua National Monument, Lost Canyon, just E of junction with Surprise Canyon, 2 Jul 1975, T. Reeves R3253(LL). New Mexico: Guadalupe Mountains, 24 Aug 1901, Bailey 454 (US); Alamo National Forest, head of Rio Fresnal, 12 Aug 1911, Barlow s n (UCLA); Otero County, Lincoln Forest, La Luz Canyon, 2000 m, 20-30 Jun 1918, Eggleston 14361 and 14366 (US); New Mexico County, fl, 18 May 1938, Goodding 6574 (ARIZ); New Mexico County, E of Tularosa on highway to Roswell, A. L. Hinckley 6567 (ARIZ); Sacramento Mountains, Fresnal Canyon, ca 1900 m, fr, 24 Aug 1916, Rehder 427 and 431 (US); near Queen, 20-21 Aug 1924, Standley 40687 (US); Rescine, 9 Sep 1935, Vaughan 1799 (ARIZ); Otero County, 3 mi S of Mescalero Agency, Tularosa Creek, ca 2100 m, 19 Jul 1928, Wolf 2784 (RSA, UCLA);
Mescalero Indian Reservation, 2 mi above Mescalero, S fork of Tularosa Creek, Wolf 2824 (POM, UCLA, US); Otero County, Sacramento Mountains, Fresnal, fr 21 Jul 1899, Wooton s n (ARIZ, POM, US); Lincoln County, White Mountains, Tularosa Creek, 6 Aug 1901, Wooton s n (US). Texas: Brewster County, Big Bend National Park, ca 2100 m, st, 13 Jul 1972, Chiang, Wendt & M. C. Johnston 8420f (TEX); Brewster County, Chisos Mountains, Big Bend National Park, below Emory Peak, fl, 17 Jun 1964, Correll 29751 (TEX); Correll & Hanson 29821 (TEX); Jeff Davis County, Davis Mountains, Upper Limpia Canyon, Ferris &
Duncan 2528 (CA, DS); upper ravines of Chisos Mountains, fr, Aug 1893, Havard 129 (US); Jeff Davis County, Mt Livermore, gorge of Goat Canyon, 26 Jul 1937, L.C. Hinckley 985a (TEX); Jeff Davis County, Mt Livermore, ca 2400 m, st, 13 Oct 1934, L. C. Hinckley s n (TEX);
Jeff Davis County, Mt Livermore, ca 2100 m, fr, Jul 1937, L. C. Hinckley s n (TEX); Chisos Mountains, 1200-2000 m alt, 9 Sep 1937, Marsh 354 (TEX); Brewster County, Chisos Mountains State Park, 30 Aug 1935, Marsh s n (TEX); Presidio County, Horse Creek ca 2 mi above Barnett Brothers Ranch, lower canyon NE of Chinati Peak, 20 Jul 1945, McVaugh 7445 (TEX); Brewster County, Chisos Mountains, above Boot Springs, 2120 m alt, fl, 21 Jun 1931 J. A. Moore &
Steyermark 3161 (CA, UC, US); Jeff Davis County, Davis Mountains, fl, 15 Jun 1926, E.J. Palmer 30919 (US); Jeff Davis County, Davis Mountains, fr, 7 Oct 1926, E.J. Palmer 31992 (US); Jeff Davis Co., Davis Mountains, 2200 m alt, fl, 4 Jun 1928, E. J. Palmer 34337 (US); Brewster County, Chisos Mountains, Big Bend National Park, upper Green Gulch, 22 Aug 1947, Tharp 5100 (TEX);
Brewster County, Chisos Mountains, Green Gulch, 22 Aug 1947, Tharp, Warnock & L. C. Hin- ckley s n (TEX); Brewster County, Chisos Mountains, Mt. Emory, 2100-2400 m alt, fr, 26 Aug 1937, Warnock 1023 (TEX); Warnock 6843 (TEX); Brewster County, Chisos Mountains, Big Bend National Park, between Boot Spring and S rim along upper Boot Canyon, ca 2100 m alt, 15 Jul 1955, Warnock 12713 (TEX); Chisos Mountains, 9 Aug 1915, Young s n (TEX). MEXICO.
Chihuahua: Canyon in N face of Sierra Rica S of Rancho La Consolacion, 1400-2000 m alt, fl, 3 May 1973, M. C. Johnston et al-10754 (TEX). Coahuila: 1 mi W of Mineral Padilla, 16 m E and 18 mi N of Ocampo, fl, 13 Jun 1956, Graber 135 (TEX); Sierra del Pino, W of camp La Noria, 24
El Popo, 1550 m alt, fr, 28 Sep 1973, M. C. Johnston, Chiang, Wendt, Riskind 11859 (TEX); 17 km N of Rancho El Jardin and ca 5 km SW of Mina El Popo, Sierra del Carmen, 1750-2000 m alt, fr, 28 Jul 1973, M. C. Johnston, Wendt, Chiang & Riskind 11886 (TEX); Sierra del Carmen, Mina El Popo ca 2 km S of Canon del Diablo and ca 19 km N of Rancho El Jardin, fr, 29 Jul 1973, M.
C. Johnston et al 11924 (TEX); Sierra de Santa Rosa, S of Muzquiz, 14 Jul 1938, Marsh 1389 F, GH, TEX); Gloria Mountains, Monclova, 4 Aug 1939, Marsh 1938 (F, GH, TEX); Sierra de la Madera, Canon del Pajarito, municipio de Cuatro Cienegas, 6 Sep 1939, C. H. Muller 3188 (GH, NA); Carneros Pass, ca 1500 m alt, fr, 15 Sep 1889, Pringle 2810 (GH); 29?07'N 102?27'W, 24 Aug 1953, Warnock 11604 (TEX). Nuevo Leon: 14 km W of Tokio on San Roberto-Galeana highway, 2000 m alt, 17 May 1973, M. C. Johnston, Wendt & Chiang 11051 (TEX); municipio de Mon- temorelos, trail from La Trinidad up Sierra de la Cebolla, fr, 20 Aug 1939, C. H. Muller 2872 (GH, NA); Sierra Madre Oriental, W side of divide between San Francisco Canyon and Pablillo, 15 mi SW of Pueblo Galeana, ca 2600 m alt, 14 May 1934, C. H. & M. T. Muller 399 (A, F, MICH, TEX,); Sierra Madre Oriental, lower San Francisco Canyon, ca 15 mi SW of Pueblo Galeana, 2300-2400 m alt, 13 May 1934, C. H. & M. T. Muller 455 (A, F, TEX, MICH); Sierra Madre Oriental, ascent of Sierra Infiernillo, ca 15 mi SW of Galeana, fl, 17 Jun 1934, C. H. & M.
T. Muller 846 (F, TEX, MICH); Sierra Madre Oriental, W side of lower San Francisco Canyon, fr, 15 Jul 1934, C. H. & M. T. Muller 1034 (A, TEX); Granadilla, Cerro de la Silla, near Mon- terrey, ca 1200 m alt, fr, 23 Jun 1972, S.S. White 1485 (ARIZ, GH, MICH, US); Galeana, Hac- ienda Pablillo, fr, 8 Aug 1936, Taylor 98 (ARIZ, F, TEX). Tamaulipas: Sierra de Guatemala, municipio de Gomez Farias, between Julio and Las Canoas, 1400-1800 m alt, fl, 23 Jun 1971, Sullivan 590 (ENCB, TEX); municipio de G6mez Farias, Rancho del Cielo, fl, Spring 1965, M. B.
Webster 134 (TEX); municipio de G6mez Farias, between Rancho del Cielo and Charco de los Perros, 1200-1800 m alt, fr, spring 1965, M. B. Webster 146 (TEX). San Luis Potosi: Mountains ca 10 mi NE of Ciudad del Maiz, 1400-1600 m alt, fr, 8 May 1949, McVaugh 10454 (MICH);
Sierra de Alvarez, ca 40 km ESE of San Luis Potosi, 2200 m, fr, 19 Sep 1963, McVaugh 22161 (MICH); Alvarez, fr, 5-10 Sep 1902, E. Palmer 57 (A, F, GH, US); Alvarez, 13-23 Jul 1904, E.
Palmer 214 (F, GH, US, MICH); 1900-2400 m alt, 1878, Parry & E. Palmer 116 (GH, NA, US);
Sierra de Alvarez, 2100-2300 m alt, fr, 30-31 Jun 1934, Pennell 17810 (US); Minas de San Rafael, Bagre, fl, Jun 1911, Purpus 5330 (F, GH, MEXU, US); road from San Luis Potosi to Rioverde, km 65, 1500 m alt, 11 Sep 1954, Rzedowski 4504 (ENCB); ca 8 km NE of Guadalcazar, 1900 m alt, 11 Nov 1955, Rzedowski 6818 (ENCB, TEX); road from San Luis Potosi to Rioverde, km 42, 2100 m alt, fl, 10 Jun 1956, Rzedowski 7741 (ENCB, MICH, TEX); road from San Luis Potosi to Rioverde, km 50, 13 Sep 1956, Rzedowski 8050 (ENCB). Hidalgo: 7 km N of Mdxico state line on expressway to Tula, 2100 m alt, fr, 25 Jun 1972, Chiang, Wendt & M. C. Johnston 8128 (TEX);
Penas Largas, near Tezoantla, municipio de Real del Monte, 2750 m alt, fl, Rzedowski 22190 EN- CB, MICH); municipio de Real del Monte, Pefias Largas, near Tezoantla, 2750 m alt, fr, 14 Aug 1966, Rzedowski 22937 (ENCB). Mexico: near Ayucan, Cerro Chiluca, Aug 1952, Paray 361 EN- CB); near San Martin de las Piramides, N of Cerro Gordo, 2900 m alt, fl, 6 Mar 1966, Rzedowski 22021 (ENCB, F, MICH, TEX); municipio de Texcoco, 2 km SE of San Pablo Ixayoc, 3 Aug 1967, Rzedowski 24180 (ENCB); near San Martin de las Piramides, near the peak of Cerro Gordo, 3000 m alt, 17 Aug 1971, Rzedowski 28525 (ENCB); municipio de Naucalpan, 1 km W of Rio Hondo, 2300 m alt, fl, 20 Feb 1972, Rzedowski 28825 (ENCB, MICH). Distrito Federal: Valley of Mexico, fr, 1866, Bourgeau 698 (US); Pedregal de San Angel cerca de Eslava, 11 Jul 1965, Espinosa 710 (ENCB, TEX); Contreras, fl, 19 Feb 1956, Paray 1907(ENCB); Valley of Mexico, Eslava, ca 2300 m alt, fl & fr, 31 Jan 1899, Pringle 8055 (A, F, MEXU, MICH, POM, US); Eslava, ca 2200 m alt, fl, 17 Apr 1904, Pringle 11947 (F, GH-mixed with R. mucronata); Tontepec, fr, May 1914, Reiche s n (US, MEXU); Cerro de Tontepec, Prefectura de Guadalupe Hidalgo, Jun 1914, Reiche s n (MEXU, US); Valley of Mexico, Chapultepec, 14 May 1899, Rose & Hough 4233 (US); SE part of Pedregal, near railway FFCC, 16 May 1952, Rzedowski 981 (ENCB); SW of Cerro Zacayuca, fl, 11 Jan 1953, Rzedowski 2266 (ENCB); delegaci6n de V. Alvaro Obregon, 4 km SW of Santa Lucia, 2500 m alt, 23 Apr 1970, Rzedowski 27245 (ENCB, MICH-one sheet at TEX with same number is R. mucronata). Morelos: Huitzilac, Oct 1930, Lyonnet 745 (A, US). Chiapas:
Municipio de San Crist6bal de las Casas, Cerro San Crist6bal, 2180 m alt, fr, 29 Aug 1966,
