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En el estado de Hidalgo se distribuyen, naturalmente, 12 especies de pinos, de las cuales, Pinus pinceana y P. greggii están clasificados en categorías de riesgo. En este contexto es necesario generar información para la identificación taxonómica de Pinus, únicamente con base en caracteres anatómicos de acículas en individuos jóvenes que carecen de estróbilos femeninos. El objetivo del presente estudio fue establecer una clave dicotómica para la identificación de pinos de Hidalgo, a partir de su anatomía foliar. Se recolectaron ejemplares en diversas localidades, se obtuvieron cortes transversales de las acículas, con ellos se codificó una matriz de caracteres, la cual fue sometida a un análisis de similitud UPGMA; y se elaboró una clave taxonómica. Se logran diferenciar 10 de los 12 taxones, que incluyen a Pinus greggii, especie bajo categoría de riesgo. Pinus cembroides se diferencia de P. pinceana, solo cuando la forma de la acícula, en corte transversal, es semicircular. Los canales resiníferos externos se observaron solamente en individuos del subgénero Strobus; y los septales en P. oocarpa. El número de canales resiníferos es utilizado de manera complementaria para identificar, debido a su alta variación. El análisis UPGMA resultó en dos agrupaciones principales, en la primera se recuperaron dos subgrupos correspondientes a las especies del subgénero Strobus y del subgénero Pinus; en la segunda pertenecen al subgénero Pinus. Se concluye que la clave es robusta para la identificación de especies de pinos a escala local, exclusivamente mediante caracteres anatómicos foliares.

It is well known that inherent characteristics of forest species constitute the main control of litter decomposition. In mixed forest, chemical interactions occurring through precipitation turn mechanisms of litter decomposition very uncertain and difficult to predict. Early-stage leaf litter decomposition of Quercus potosina and Pinus cembroides and their controls were examined based on Ostrofsky’s decomposition mechanisms. From June 2007 to May 2008, litterbags with pure and mixed leaf-litter of Q. potosina and P. cembroides were incubated in situ in monospecific and mixed tree stands, respectively. Sampling was carried out 3, 6, 9, and 12 months after incubation. After 12 months, two phases of decomposition of pure and mixed litter were identified; an early phase with a greater rate of mass loss of the labile litter fraction (kL; soluble compounds) and a later phase with a lower rate of mass loss of the recalcitrant litter fraction (kR; lignin). The labile fraction lost was observed at three and 6 months of incubation, which coincided with the months of highest rainfall likely triggering a rapid release of soluble carbon compounds from leaf litter. Results also indicate that leaf-litter from Q. potosina had higher concentration of soluble compounds and lower lignin concentration than leaf litter from P. cembroides. Observed facilitative and inhibitory mechanisms for mass loss in Q. potosina and P. cembroides were controlled by interaction between physico-chemical litter characteristics and rainfall.

We recorded 156 taxa of legumes, comprising 50 genera, 152 species, and 34 infra-specific taxa, in the southern part of state of Nuevo Leon. Genera with the highest numbers of species were Dalea (19), Desmodium (12), Acacia (10), Astragalus (10), Phaseolus (8), Mimosa (8), Lupinus (7), and Senna (6). The growth forms were herbaceous species (49% of species), shrubby species (33%), twining and climbing species (16%), and arboreal species (2%). The highest numbers of taxa were in oak-pine forest (95), coniferous forest (excluding Pinus cembroides) (93), oak forest (59), and Pinus cembroides forest (56). Based on legume distribution in different plant communities, 3 distributional patterns were recognized: 1) shrublands and halophytic grasslands; 2) oak, oak-pine, coniferous (other than Pinus cembroides), and Pinus cemborides forests and piedmont scrub; and 3) subalpine prairie.

We tested the effect natural products smoke has on the honey bee tracheal mite (Acarapis woodi) and honey bees. Plant materials screened for activity included coffee beans (Coffea arabica), corncobs (Zea mays), creosote bush (Larrea tridentata), eucalyptus (Eucalyptus sp.), orange peel (Citrus sinensis), pecan leaves (Carya illinoiensis), dead and fresh pine needles (Pinus cembroides), mesquite leaves (Prosopis glandulosa) and tobacco (Nicotiana tabacum). Low but significant mite mortality was caused by the smoke of pine needles, mesquite, corncobs, and coffee beans. The smoke of L. tridentata killed more adult A. woodi than other materials (LT50 = 2.4 min, single exposure). It was not effective against immatures. Mite mortality was negatively correlated with parasites/trachea, suggesting that reduced air flow while breathing may have reduced efficacy. Efficacy was modest (ca. 70%) and it caused transitory bee anesthesia. We do not recommend using this material as a control. creosote bush / Larrea tridentata / smoke / Acarapis woodi / secondary plant products

A method (FungiLog) was developed that allows a quantitative approach to examining aspects of fungal functional diversity. The BIOLOG microti- ter plate method for measuring bacterial functional diversity was modified for use with fungal assemblag- es. Each BIOLOG plate contains 95 different carbon substrates. Eight different tetrazolium dyes were eval- uated and dimethylthiazolyl-diphenyltetrazolium bro- mide (MTT) was chosen as the most suitable indi- cator of fungal growth. Procedures for inoculum preparation from a variety of substrates and inocu- lation into modified BIOLOG SF-N microplates were devised. By also plating out inoculum used to inoc- ulate the FungiLog plates, taxonomic data can be ob- tained in conjunction with functional diversity. The FungiLog method was subsequently evaluated for de- tecting landscape patterns of fungal functional diver- sity using decaying lechuguilla (Agave lechuguilla) leaves placed along an elevational gradient in Big Bend National Park, Texas, in 5 vegetation zones. Sites ranged from a high elevation (2098 m) zone dominated by live oak (Quercus emoryi) and pinyon pine (Pinus cembroides) to a low land Chihuahuan Desert scrub (973 m). Ten, preweighed, 10-cm pieces of lechuguilla leaves were collected from each vege- tation zone, 5 per transect, after 6 mo decomposi- tion. FungiLog data were used to calculate two mea- sures of fungal functional diversity, substrate richness and total activity. FungiLog patterns distinguished differences in total activity and substrate richness among the low elevational and the high elevational sites at this stage in the decomposition of lechuguilla leaves. Furthermore, litter decomposition was greater

Mineral analysis of seven Pinus species grown in different regions of New Zealand, Armand pine (Pinus armandii Franch), Swiss stone pine (Pinus cembra L.), Mexican pinyon (Pinus cembroides Zucc. var. bicolor Little), Coulter pine (Pinus coulteri D. Don), Johann’s pine (Pinus johannis M.F. Robert), Italian stone pine (Pinus pinea L.) and Torrey pine (Pinus torreyana Parry ex Carrière), was carried out using an inductively coupled plasma optical emission spectrophotometer (ICP-OES) analysis. Fourteen different minerals (Al, B, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S and Zn) were identified in all seven varieties, except that no Al or Na was found in Pinus coulteri D. Don. New Zealand grown pine nuts are a good source of Cu, Mg, Mn, P and Zn, meeting or exceeding the recommended RDI for these minerals (based on an intake of 50 g nuts/day) while they supplied between 39%–89% of the New Zealand RDI for Fe. Compared to other commonly eaten tree-nuts New Zealand grown pine nuts are an excellent source of essential minerals.

The fatty acid composition of the edible seeds from Pinus cembroides edulis (a nut pine), that might have been a commercial source of Δ5-olefinic acids in the United States, has been established. The dehulled seeds are rich in oil (64% by weight) and are characterized by high levels of both oleic and linoleic acids (ca. 47 and 41%, respectively), with only 10% of saturated acids. Δ5-Olefinic acids, which were not reported previously in this species, are exceptionally low as compared to most other conifer species: 5,9-18:2 acid, 0.1%; 5,9,12-18:3 acid, 0.4%; 5, 11, 14-20:3 acid, 0.3%. In this respect, P. cembroides edulis seed oil closely resembles that of P. pinea (a circum-Mediterranean species), which emphasizes the morphological and taxonomic relationship between the sections to which the two species belong (Parryana and Pinea, respectively).

Fatty acids from oils extracted from three seed coat phenotypes of Mexican stone pines (Pinus cembroides Zuc) growing in the central region of Veracruz State, Mexico, consisted of lauric (0-4.8%), myristic (3.4-9.1%), palmitic (6.4-7.8%), stearic (3.1-5.5%), oleic (36.7-47.2%) and linoleic (32.9-44.5%) acids. The differences between the phenotypes studied were statistically significant in their levels of myristic, oleic and linoleic acids.

The Orizaba pinyon (Pinus cembroides subsp. orizabensis) is raised to specific status. Pinus orizabensis differs from P. cembroides in many characters, including needle and bark morphology and terpene chemistry. Orizaba pinyon, Pinus cembroides Zucc. subsp. orizabensis D. K. Bailey, is a local taxon of east central Mexico described by Bailey (1983). The taxon is here raised to specific rank because of marked differences in needle and bark morphology and terpene chemistry between it and P. cembroides. Pinus orizabensis (D. K. Bailey) D. K. Bailey & Hawksworth, comb. et stat. nov. Basionym: Pinus cembroides Zucc. subsp. orizabensis D. K. Bailey, Phytologia 54: 89. 1983. TYPE: Mexico. Puebla: Mpio. Soltepec, ca. 10 km SW of San Salvador el Seco on Highway 140, 19?04'N, 97?42'W, 2,370 m, 1983, D. K. Bailey 83-01 (holotype, MEXU; isotypes, ARIZ, CHAPA, COLO, E, ENCB, INIF, K, MO, NY, RM, TEX, UC, US, UTC). Pinus cembroides, as interpreted by Bailey (1983) and Bailey & Hawksworth (1988), was considered to be comprised of three allopatric subspecies: 1. Subspecies cembroides, the most widespread taxon, ranging from northern Chihuahua and west Texas throughout the Sierra Madre Occidental and Sierra Madre Oriental to central Mexico (Hidalgo and northern Veracruz). 2. Subspecies lagunae (Robert-Passini) D. K. Bailey, a local endemic restricted to the Sierra Laguna in southern Baja California. 3. Subspecies orizabensis D. K. Bailey, a local endemic in Puebla, Tlaxcala, and Veracruz. Since that time there has been a trend to accept subspecies lagunae as a distinct species, Pinus lagunae M.-F. Passini (1987), e.g., in the recent compendium of the pines of Mexico and Central America (Perry, 1991). However, because the differences between subspecies cembroides and orizabensis are greater than those between subspecies cembroides and lagunae, we suggest raising subspecies orizabensis to species rank as well. Pinus orizabensis and P. cembroides are not sympatric, and the gap between them is about 140 km (Bailey, 1983). The two pines differ in several morphological, chemical, and ecological features (Bailey, 1983), some of which are listed in Table 1. Acknowledgment. We thank Teobaldo Eguiluz Piedra, Director, Centro de Genetica Forestal, Chapingo, Mexico, for encouraging us to make this new combination. TABLE 1. Comparisons of some characters of Pinus orizabensis and P. cembroides. Character P. orizabensis P. cembroides Needle number per fascicle Range 2-5; ca. 75-95% in 3's, Range 2-4; ca. 60% in 2's and 40% 5-20% in 4's in 3's Needle color Dorsal surface bluish-green; ventral Dorsal surface yellow-green; ventral surface markedly glaucous surface slightly glaucous Bark of mature trees Thin, little transverse fissuring, inner Thick, strong transverse fissuring, inbark conspicuous, orange ner bark inconspicuous, yellow Monoterpenes 3-carene usually less than 1% 3-carene usually ca. 10% Main elevational range 2,300-2,700 m 1,700-2,400 m NOVON 2: 306-307. 1992. This content downloaded from 157.55.39.132 on Thu, 15 Sep 2016 06:14:45 UTC All use subject to http://about.jstor.org/terms Volume 2, Number 4 1992 307 Bailey & Hawksworth Pinus cembroides subsp. orizabensis

Interactions between two endemic species were studied at the Sierra de La Laguna, Baja California Sur, Mexico. Structural characteristics of the madrone (Arbutus penznsularis), such as crown cover and distribution of inflorescences within the crown, as well as flower availability were determined and related with frequency of visits and foraging time expended by the Xantus' hummingbird (Z-lylocharr~ xantusii). Our results show a relation between those crown sections of madrones where hummingbirds spend most of their foraging time and success in flower fertilization. It seems that madrones need hummingbirds to fulfill pollination and that flowers of madrones are almost the only nectar supply for If. xantusii during the critica1 late-winter months, so we suggest that these species are mutually dependent. It is well known that plant-animal long-term interactions can result in coevoiutionary processes , . in which characters of both species are mutually influenced by relationships which lead to reciproca1 dependence (Lyon and Chader, 1971 ; Janzen, 1980; Feinsinger, 1983; Montgomerie et al., 1984; Macior, 1986). Coevolution between several characteristics of hummingbirds (Trochilidae) and floral features of several plant families has been well documented (Price and Waser, 1979; Ewald and Williams, 1982; Montgomerie et al., 1984). Floral adaptations in corolla length, nectar volume, and nectar concentration and their relationships to body size, nectar extraction rates, and bill size for hummingbirds have also been studied in detail (Stiles, 1976; Montgomerie, 1984; Brown and Bowers, 1985). We suggest, however, that other structural characteristics in plants can also be closely related to bird interactions, especially in simplified ecosystems, such as virtual islands, where these characteristics may be highly apparent and easily recognizable. In this work, we studied some interactions between two species, an endemic madrone and an endemic hummingbird, of the Cape Region in Mexico. Our principal aim was to determine whether an association exists between these species by describing some structural characteristics of the madrones, such as crown cover and distribution of inflorescences within the crown as well as flower availability, and frequency of visits and foraging time expended by hummingbirds over the diff'erent parts of the trees. MATERIALS AND METHODS-The study was conducted at the "Sierra de La Laguna" located between parallels 22"50'N and 24"N and 109"60'W and llO"lOfW in a pine-oak forest which covered 20,000 ha (Villa-Salas, 1968) at an altitude of 1,800 to 2,200 m in the Cape Region, southern Baja California, Mexico. The total annual rainfall was 700 mm and was highly concentrated during summer with a mean annual temperature of 14.5"C. The climate corresponded to "temperate humid" in the classification of Garcia (1981). Vegetation of the study area was forest dominated by Pinus cembroides var. lagunae and Quercus deuza, with some other species of less structural importance such as Quercus tuberculata, Arbutus peninsularis, and Nolina beldingii. The Sierra de La Laguna represented a true vegetation island surrounded by thousmds of kilometers of desert and sea. At present, the Centro de Investigaciones Biologicas is promoting its legal protection as a Biosphere Reserve because of its great ecological importance and because it represents the main aquiferous recharge zone of the state of Baja California Sur. Arbutuspeninrularis (Rose and ~o ld rnan ) , a member of the family Ericaceae and an endemic tree (3 to 40 m tall) of the Cape Region, grew in hillsides and canyons of the pine-oak forest and was an important physiognomical element of this forest. Madrones have flowMarch 1990 Arriaga et al.-Endemic hummingbirds and madrones of Baja 77 TABLE 1-Flower conditions (percent) recorded according to crown strata in Arbutus peninsularis of the Sierra de La Laguna. Percentages are calculated for conditions within given straturn. Sample sizes are total nurnber of flowers with number of inflorescences in parentheses. Position within crown Flower condition Lower Medium U P P ~ ~ n = 2,205 (32) n = 2,580 (42) n = 1,828 (36) Fertilized flowers forrning fruits 44.94 49.42 65.43 Closed flowers 25.23 21.98 29.32 Flowers with rotten ovules 2.27 2.21 1.64 Flowers with evidences of herbivory 5.92 9.11 2.02 Flowers affected by unknown causes 21.63 17.29 1.59 ers in terminal panicles, with pale pinkish corollas, swollen toward the base and with lobes much shorter than tube (Wiggins, 1980). ffylocharis xantusit (Vieillot), a Cape Region endemic hummingbird, has an average weight of 3.5 g, with a wing length of 49.3 rnrn and a culrnen length of 17.0 mm (Brown and Bowers, 1985). The biology and ecology of these two species rernain almost unknown. The fieldwork was conducted from 24 February to 17 March 1987 during part of the flowering period of the rnadrones. A linear transect of 950 by 80 m was established along a canyon where the greatest density of madrones was found. Within the transect, al1 madrones were rnarked and nine points were selected according to tree density. Five trees were randornly selected in each point, and the following features were recorded per tree: total height, crown height, crown cover, diameter at breast height. The crown height was stratified in three equivalent sections: 1) upper crown (UPC); 2) rnedium crown (MEC); 3) lower crown (LOC). The total nurnber of inflorescences per stratum were counted and representative subsarnples of inflorescences per stratum were obtained. The following data were recorded for each inflorescence in the laboratory: total number of flowers per inflorescence; number of irnrnature flowers; fertilized flowers; flowers with rotten ovules; number of flowers destroyed by insect attack or because of unknown causes. Hurnmingbird activity was recorded in the same sampled trees. The frequency of visits was deterrnined by observing the arrival of hurnmingbirds with Zeiss binoculars (8 x 40) from 0700 to 1800 h spending 15 rnin at each observation point during 4 days. Time spent by the hummingbirds in each stratum of the tree (UPC, MEC, and LOC) was also recorded. Behavioral patterns, such as foraging time and territorial display time, were discerned for each individual as related to the total time spent by each hurnrningbird in the tree. RESULTS-Forty-five madrones were marked and analyzed for their structural characteristics. A ioial of 6,433 flowers were separated a n d analyzed, of which 32 inflorescences corresponded to LOC, 42 to M E C , a n d 36 to U P C . A total of 475 hummingbird visits were recorded. These visits covered a total time of 1,445 min. Birds spent 361 min in foraging activities and 317 min exhibiting territorial behavior by means of song a n d direci aggressions. Tab le 1 shows the differences among the percentages of t he several flower conditions recorded according to their crown layer. T h e uppe r crown s t ra ium harbors the highesi number of fertilized flowers a s well as the lowesi percent of flowers lost by herbivory and other causes. ?'he opposite occurs with the lower crown layer. A simple l inear model between crown cover (CRC) and number of inflorescences per tree (NI ) , NI = 29.705 + 2.206 CRC, was obtained (F = TABLE 2-Relative frequency of visits (percent) and percentage of foraging time spent by Hylocharis xantusii within several crown strata and at the externa1 and interna1 parts of the crown of Arbutus peninsularis. Number of observations = 475. Crown stratum Crown section Hylocharis behavior Lower Medium U P P ~ ~ Extrrnal Interna1 Frequency of visits 10.10 16.63 73.26 69.68 30.32 Foraging time 13.16 13.01 73.83 74.24 25.76 78 The Southwestern Naturalist vol. 35. no. 1 TABLE 3-Frequency of madrones assembled per crown cover category and frequency of trees intensely foraged by Hylocharis xantusii within the same crown categories (n = 45). Crown Trees Trees not cover Frequency intensely intensely categories of trees foraged foraged

Wood of Pinus discolor and Pinus johannis from 210 trees sampled in 21 localities throughout their range in the United States and Mexico has been analysed for monoterpenes. The trees of Pinus discolor produced mainly the sabinene-related monoterpenes (sabinene, thujene, γ-terpinene, terpinolene and p- cymene ) while the trees of P. johannis produced mainly α-pinene with sabinene-related monoterpenes in secondary or trace amounts. The strong chemical differences between P. discolor and P. johannis were only weakly reflected by morphology. No evidence for natural hybridization between P. cembroides subsp. cembroides and P. johannis could be obtained investgating trees from the common site.

Wood of Pinus cembroides from 232 trees sampled in 23 localities throughout its range in the United States and Mexico has been analysed for monoterpenes. With a few exceptions the trees of the continental populations from the state of Hidalgo northward produced α-pinene as the main monoterpene. The majority of trees of the southern populations (subsp. orizabensis) from the state of Puebla and adjoining regions of the neighboring Veracruz and Tlaxcala produced 3-carene in appreciable amounts. The population from Baja California (subsp. lagunae) produced monoterpenes of the sabinene family (thujene, sabinene, γ-terpinene, terpinolene and p-cymene) as the main constituents. The variations in morphological characters, including number of needles per fascicle, number of stomatal rows in needles, number of resin canals in needles, as well as other characters of the internal needle morphology, needle length and thickness, needle retention, thickness of seed shells, bark and cone characteristics, rate of growth and cotyledon number either paralleled or did not contradict the chemical variations. The evolution of the southern populations (subsp. orizabensis) into a separate group most likely resulted from geographic separation and climatic differences, while the evolutionary separation of the Baja California trees (subsp. lagunae) was connected with northwestern movement of the California coastal region from Miocene onward and the formation of Sierra Madre Occidental resulting in separation of this population from the mainland populations by the gap of the Gulf of California and the coastal mountain ranges.

Modern pollen grains from several species of Abies, Picea and Pinus occurring mainly in the Rocky Mountain region of the United States and Canada were examined using the scanning electron microscope. Distinguishing characteristics for the species were found using systematized observational and photographic methods on extensive collections. Preparation of the samples included acetolysis, critical-point drying to preserve three-dimensional morphology, and carbon-gold coating. The technique employed in preparing the pollen samples is outlined in detail in this paper. Species distinctions were based on types of morphological structures rather than on measurements of the grains or their parts; however, several subjective determinations of shape and proportion proved useful in distinguishing certain species. Pollen grains of Abies grandis, A. amabilis and A. lasiocarpa were found to differ in the morphology of the triradiate streak. Picea glauca and P. sitchensis differ in cappula morphology and P. engelmannii shows distinctive bladder proportion and placement. Pinus ponderosa differs from P. contorta on the basis of cappula morphology. Pinus monticola and P. albicaulis can, at the same time, be singled out from the other pines studied and distinguished one from the other by a combination of a cappula and cappa characteristics. Pinus cembroides is distinguished from the other pines by its characteristic cappa and P. edulis by shape, proportion and attachement of its bladders. Although Pinus monophylla showed no single distinctive morphological feature, it can be separated from the other pines studied by a process of elimination based on several characteristics.

Sixty Pinus cembroides and P. discolor trees from two mixed stands and eight pure stands were analysed for the composition of their wood monoterpenes, number of abaxial and adaxial stomatal rows and the number of needles per fascicle. While by far the majority of the characters analysed showed highly significant differences between the two species, only the sum of thujene, sabinene, γ-terpenene, terpinolene and p-cymene percentages, the sum of myrcene and cis-ocimene percentages, the number of abaxial stomatal rows, and the number of needles per fascicle could be used to evaluate the potential intermediacy of trees from the common sites. The results indicated the absence of any hybridization in the Sierra de la Catarina Mountains of Chihuathua (Mexico) and either a possible minute introgression of P. cembroides into P. discolor in the San Miguelito Mountains of San Luis Potosi (Mexico) or a slightly different genetic composition of the trees from this site. The results strongly support the proposal of Bailey and Hawksworth to regard P. discolor as a distinct species.

Wood of Pinus remota from 126 trees sampled in 13 localities throughout of its ranges in the United States and Mexico has been analysed for monoterpenes. The trees of P. remota produced mainly α-pinene and limonene with ranges for population means of 68.0–92.3% and 3.2–16.9%, respectively. Limonene was useful for distinguishing this species from subsp. cembroides . Small chemical differences were found between the eastern and western variants of P. remota . The chemical differences between the trees of P. remota from the United States and the trees of the newly described species, P. catarinae , from Mpo Santa Catarina near Saltillo, Mexico, were also very few and quantitatively small. The variations in morphological characteristics paralleled the chemical differentiation. The chemical and morphological data substantiated the species status of P. remota , and suggested the status of a mere marginal variant for P. catarinae .

The composition of gum turpentines from three species of Mexican pines has been determined. Each sample was fractionated and its components have been investigated and reported.

Two new species of Cercocarpus are described from limestone areas in the Sierra Madre Oriental in eastern Mexico. Cercocarpus mexicanus appears most similar to the C. montanus complex, but has prominent stomatal crypts as in C. fothergilloides; it differs from both in its thickened leafblades with distinct rows of conspicuous stomatal crypts on the abaxial leaf surface. Cercocarpus rzedowskii is similar to C. ledifolius but differs in the absence of bundle sheath extensions in leaves. In leaf and stem vestiture it has similarities with C. fothergilloides. Recent field studies in Sierra Madre Oriental of Nuevo Leon, Tamaulipas, and San Luis Potosi, Mexico have uncovered two new species of Cercocarpus (Rosaceae) that are chaparral dominants. The species are described herein. Cercocarpus mexicanus Henrickson, sp. nov. (fig. la-c).-TYPE: Mexico, Nuevo Leon, Santa Rita, Galeana, 2100 m, 25 Apr 1981, G. B. Hinton 18191 (holotype: TEX!; isotypes to be distributed).-PARATYPES: Mexico, Nuevo Leon, ca. 15 air km SW of Galeana on W slope of mts. just S of Cerro Potosi above old abandoned settlement at Santa Rita de Cardeladas on limestone slopes with Pinus cembroides, Rhus virens, Lindleya, Mortonia, Garrya, Chrysactinia, Forsellesia, Gochnatia, ca. 2100-2200 m, near 24?46'N lat, 100?13'W long, 10 Oct 1982, Henrickson & Hess 19295 (TEX, MOR, and to be distributed); ca. 30 km ENE of Dr. Arroyo, 2.5 km ENE of San Antonio de Pefia Nevada, W base of Cerro Pefia Nevada, above gypsum on limestone, 6600 ft, 3-5 Aug 1981, Nesom 4294 (TEX). A speciebus omnibus aliis genus laminis foliorum valde incrassatis 0.5-0.8 mm crassis, venis secondariis crassis arcuatis corneis, areis inter venas secondarias cryptis stomatiferis conspicuis 2-4-seriatis instructis differt. Much-branched, erect, obovoid shrubs (0.5)0.7-2 m tall, 0.5-1 m in diam.; stems erect, ascending, many from base; young stems dark maroon, strigose with antrorse hairs 0.2-0.6 mm long, glabrate, with internodes 5-20 mm long; older stems mottled gray-silver; periderm roughened with age; upper stems bearing many ascending to divergent short shoots 1-14 cm long, 1.5-3.2 mm in diam. with internodes ca. 1 mm long, these branching, occasionally reverting to long shoots for 1-2 seasons. Leaves erect-ascending; petioles (1.5)3-5(6) mm long, broadly clasping at very base, 3-angled, canaliculate adaxially above base, strigose as young stems, dark maroon to yellowish-green; stipules maroon-brown, thin but coriaceous, adnate to basal petiole margins for 1-1.5 mm, terminating in acute-acuminate tips 0.5-1(2) mm long, strigose abaxially, glabrous adaxially, eventually deciduous; leaf-blades stiffly coriaceous, elliptical, narrowly ovate, narrowly obovate to ovate, (12)17-31 mm long, (6)10-15(17) mm wide, 0.50.8 mm thick, rounded to obtuse at tips, narrowly to broadly cuneate at bases with lower margins entire, convex, pinnately veined with 4-7 ascending, slightly arcuate secondary veins, each terminating in a serration or dentation (0.5)1-2 mm long in distal one-half to one-third of blade, distal teeth usually reduced, all teeth usually terminating in narrow, blunt, conical, eventually darkened tips 0.2-0.5 mm long; lamina flattened or conduplicate, folded along lower midrib, weakly strigose, subglabrate, green to yellow-green on both surfaces; midveins and often secondary veins impressed above, yellowish, corneous, flattened, 0.4-0.6(1.0) mm wide, sparsely sericeous beneath; secondary veins 0.41.2(1.7) mm apart, separated by distinct bands of stomatal crypts in (1)2-4 irregular rows beneath (fig. 2b-c), crypt openings circular or variously elongate, 0. 1-0.4(0.7) mm long, with marginal rims flattened in fresh or hydrated leaves, slightly raised in dried leaves, densely sericeous on inner rims with white, straight hairs that extend into crypts (fig. 2a). Flowers 1(3) in axils of leaves or reduced bracts; bracteoles textured and colored as stipules, conduplicate