New or Noteworthy Species of Flowering Plants from the Sierra Madre de Sur of Guerrero and Michoacán , Mexico

The Sierra Madre del Sur of Pacific coastal Mexico has been of limited accessibility and therefore not wel1 explored botanical1y. Only G. B. Hinton and E. Langlasse have made significant col1ections from the area. More recent col1ections by the authors have resulted in the recognition of nine new species, described herein as follows: Acanthaceae-Elytraria rnexieana; Malvaceae-Bastardiastrurn batesii, Gossypiurn sehwendirnanii, Hibiscus zygornorphus, Kosteletzkyajlavieentrurn, Periptera lobelioides, Sidafastuosa, and Sida prolifiea; and TumeraceaePiriquetia rnexieana. Other species meriting specific comment include Dioseorea insignis (Dioscoreaceae), Anotea jlavida (Malvaceae), and Helieteres rekoi (Sterculiaceae). Illustrations of the new species and a key to the described Mexican species of Elytraria are included.


INTRODUCTION
The Sierra Madre del Sur runs from northwest to southeast, parallel and very close to the Pacific coast, from Jalisco to the Isthmus of Tehuantepec (Fig. 1; Rzedowski 1978, pp. 24-25).In Michoadm and Guerrero the Sierra is relatively inaccessible because of the lack of roads, and for this reason the flora is poorly known.In earlier times G. B. Hinton and his collaborators (Hinton andRzedowski 1972, 1975) and E. Langlasse (McVaugh 1951) were the principal botanists who made botanical collections from this region.In 1982 and1983 we explored this area by means of a new highway between Cd.Altamirano and Zihuatanejo and other available roads that permitted access.The flora there is relatively rich, and among the collections made, the following represent new or notable species meriting comment.Conventional acronyms are used to indiate herbaria of deposit of specimens, except that "pf' refers to the senior author's herbarium, kept in College Station, Texas.
Perennials from a woody root, acaulescent or more commonly with a woody, leafless stem up to 10 cm long, bearing leaves in a terminal rosette, older plants with I-several such stems arising from the original crown.Leaves narrowly to broadly spatulate, acute to acuminate at the apex, attenuate basally to a more or less winged petiole, the larger leaves 5-12 cm long and 1-3.5 cm wide, sparsely to densely villous on both surfaces with hairs to 1.5(-2) mm long, lower side paler than the upper, irregularly denticulate to nearly entire, remotely notched and sometimes with a few rounded teeth toward base.Peduncles to 20 cm long, villous beneath the bracts, wiry, erect to decumbent, occasionally proliferous, covered by imbricate, abruptly acuminate, spinulose bracts 1.5-4 mm long, with up to 7 branches, these up to 10 cm long, each branch terminating in a spike; spikes 1-4 cm long, straight and erect or curving upward, cylindric but tapering upward slightly; flowers solitary and sessile in the axils of conspicuous, imbricate bracts and subtended by a pair of inconspicuous, adaxial bracteoles; floral bracts rigid, overlapping 113-1 12 their length, 3.5-5 mm long, floccose-villous on back, especially toward the margins, ovate with slightly broadened, white margins only on lower half, narrowed to an acuminate, spinose tip; bracteoles 2.5-3 mm long, reaching to about the middle of the calyx, lanceolate, acuminate and sometimes aristate, the costa green and sparsely villous with narrow-based hairs, the margins broad and hyaline; sepals 4, nearly distinct, 3.5-4 mm long, hyaline except for the costa, villous on back and margin toward the apex; lateral sepals lanceolate, acuminate, and aristate, with convex costae; the anterior and posterior sepals broader, with concave costae forming a shallow groove in the lower part, the anterior bidentate and 2-aristate, the posterior merely acute; corolla bilabiate, the tube straight and narrow, 4-5.2 mm long, the upper lip 2 mm long, purple or blue, 2-lobed, the lobes 1 mm long, the lower lip white, divided nearly to the base into 3 subequal lobes, these 3.5-4 mm long, narrowed basally, broadened apically and divided into 2 divergent, straight-sided, secondary lobes, the margins entire except for 1-2 narrow teeth sometimes shown on the secondary lobes (not shown in Fig. lB); stamens 2, the filaments short, the anthers 0.8 mm long, positioned beneath the upper corolla lip, the thecae muticous and slightly divergent below, staminodia absent; ovary superior, the style filiform, broadened upward into a spatulate lamina, this folded around and enclosing the anthers in bud and early anthesis, bearing an apical stigmatic zone.Capsules 3-3.5 mm long, ovoid, acuminate,  Rzedowski 1978, Fig. 4).Enlarged portions of Michoacan and Guerrero show localities referred to in text and in specimen citations.The "X" indicates the type locality for Piriquetia mexicana.short-stipitate, shiny, loculicidally dehiscent from the apex, bilocular, each locule containing (6-)8 seeds, retinacula none; seeds 0.5 mm long, dark brown and pitted, with a papilla in each pit.

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Type. -GUERRERO: Mpio.de Coyuca de Catalan, 38 km al S de Cd.Altamirano, por la carretera a Zihuatanejo, ladera con pastizal, con bosque caducifolio en las cafiadas, suelo franco , alt.650 m; sobre laderas en orilla de la carretera, comun, 11 Nov. 1983 The broad, flattened style observed in Elytraria mexicana was also seen in Mexican material (Central American material was not available) of E. bromoides Oerst.and E .imbricata (Yahl) Pers.This is not in agreement with Gibson (1974, p. 363) in her generic description, nor with the illustration (Fig. 81 E, p. 365) of

E. imbricata.
Heretofore only three species of Elytraria were known from Mexico: E. macrophylla Leonard, apparently a rare endemic from the rain forest area of eastern San Luis Potosi [known to the authors only from the original description (Leonard 1939) and a photograph and fragments of the type at US]; E. bromoides, found in Texas, eastern Mexico, and Guatemala; and E. imbricata, a widespread, common species ranging from Arizona and Texas through the West Indies, Mexico, and Central America to South America, and introduced into the Old World (Leonard 1934).As far as is known, E. mexicana is restricted to the Balsas Depression (Fig. 1), where it is known along wooded streams in savannah and in areas of tropical deciduous forest.The four species can be distinguished by the characters presented in the following key:

DIOSCOREA INSIGNIS Morton & Schubert
This species was described from collections from the states of Guerrero and Mexico by Schubert and Morton (1972).In spite of its showy nature, they noted that it had been collected only a few times by Hinton et al. and never by other collectors.We encountered a staminate plant in October 1982 from another locality but were unable to find it again in November of 1983.

Malvaceae
ANOTEA FLAvIDA (DC.) Ulbrich This monotypic genus is known only from the central part of Guerrero.It was first collected by Sesse and Mocino in the 18th century; the basionym (Malva viscus jlavidus ~C.) was based on a drawing by the artists employed by Sesse and Mocino  (leones Florae Mexicanae, Tomer Collection acc.no.6331.389,Hunt Institute).No specimen of this collection is known.It was also collected in the 18th century by Haenke, whose plant is the basis of the name (synonym) Malvaviscus acerifolius K. Presl.Neither of these two old collections has a precise indication of locality.The plant remained unknown until 1967, when it was recollected to the south of Chilpancingo (Fryxell 1968), a site for several later collections (Croat 45715, Fryxell623, Fryxell & Bates 2168, Koch et al. 79125, Kruse 138).It was believed that the species (and the genus) occurred only in this small population, but in 1983 we discovered it at another locality, appreciably farther to the south.Shortly thereafter, we discovered an undetermined herbarium specimen at yet another locality.These collections are: Specimens examined.-GUERRERO: Mpio.de Acapulco, terraceria a Pablo Galeana, 2-3 km al 0 de la carretera Mexico-Acapulco (52 km al N de Acapulco); alt.680 m , 24 Nov. 1983, Koch & Fryxell83254 (BH, BM, CANB, CAS, CHAPA, CTES, ENCB, F, MEXU, MICH, MO, NY, RSA, SO, TEX, XAL, pf).Acahuizotla, adelante de Chilpancingo, entre Acahuizotla y Palo Blanco, 14 Nov. 1977, German & Funk 622 (MEXU).
Rather than being restricted to a single population, this species appears to be scattered over a relatively large area in the Sierra Madre del Sur in the central part of the state of Guerrero.
Trees to 4 m tall, the lateral branch tips tending to droop; twigs essentially glabrous, the cortex red-brown, becoming grayish bark on older branches, with neither gossypol glands nor lenticels prominent; terminal and axillary buds ferrugineous-pubescent.Leaf blades broadly ovate, up to 8 cm long, 0.9-1.1(-1.6)times as long as broad, deeply cordate to truncate, entire, acuminate, concolorous, coriaceous, glabrous (or with a few hairs beneath in the axils of the principal nerves), palmately 5-7-nerved, the nerves pallid, with inconspicuous black gossypol glands throughout blade, usually with a small nectary near base of midrib beneath; petioles 1-3 cm long, very sparsely pubescent (especially distally) to glabrate, black gland-dotted; stipules minute, caducous.Pedicels solitary (rarely paired) in the leafaxils, 4-7 mm long, stout (1-1.4 mm in diam) and thickened upward, black gland-dotted, glabrous, sometimes suffused with pink, surmounted by 3 sunken involucellar nectaries; involucellar bracts 3, erect, inserted above the nectaries, 1-2 mm long, black gland-dotted, obscurely and minutely pubescent to glabrate, triangular, sometimes obscurely 2-3-toothed; calyx 5-7 mm long, prominently black gland-dotted, campanulate, subtruncate, minutely 5-toothed, the teeth usually < I mm long, glabrous except for the minutely ciliate margin, yellowish or sometimes suffused with pink (especially on distal margin); corolla narrowly funnelform; petals 3.5-4 cm long, externally yellowish stellate-pubescent where exposed in bud, otherwise glabrous, minutely gland-dotted, with dark purple spots internally on the lower halves, distally (in sicco) yellowish suffused with lavender; staminal column glabrous, pallid, lacking black glands, 2.5-3 cm long; filaments ca. 3 mm long, arising along the entire length of column, purplish; anthers purple, pollen yellow; style exceeding staminal column, clavate, pallid, black gland-dotted, the stigmatic lobes decurrent.Capsule 2-2.5 cm long, 3-celled, narrowly fusiform, brownish, verruculate with dense, raised, black gossypol glands, externally glabrous, with a few fine hairs internally along the line of dehiscence; seeds narrowly turbinate, 10-12 mm long, 3.5-4 mm in diam, densely hairy, the hairs tan to grayish, wavy, 2-3 mm long.Gossypiurn schwendirnanii superficially resembles the widespread G. aridurn (Rose & Standley) Skovsted, which occurs along the Pacific coast of Mexico from Sinaloa to Oaxaca, extending inland to Puebla, and reported from one station in Veracruz.The new species may be distinguished from G. aridurn by the glabrous calyx and pedicel; the sometimes toothed involucellar bracts; the shorter and broader, sometimes cordate leaf blades; the distinctively different seeds (which resemble the long and narrow, grayish-pubescent seeds of G. !obaturn H. Gentry); and possibly by the drooping branch tips.The species is named for Jacques Schwendiman of the Institut de Recherches du Coton et des Textiles Exotiques, Mont-pellier, France, who first pointed out to us the distinctive nature of the wild cotton of the Infiernillo Valley.
Type. -GUERRERO: Mpio.de La Union, 20 km al N de La Union por hI.Hibiscus zygomorphus belongs to Hibiscus section Bombicella DC. (Fryxell 1980) and forms a part of the group of species with red corollas that occurs in western Mexico.It differs most markedly from these in having zygomorphic flowers (as the specific epithet indicates) with a rotate rather than a tubular corolla, and with a declined rather than a straight, exserted androecium.Other characters such as the type and distribution of pubescence also are distinctive.
Type. -GUERRERO: Mpio.de Zihuatanejo, carretera Zihuatanejo-Ulzaro Cardenas; puente sobre un desemboque, 6.5 km al NO de Zihuatanejo; orilla de la carretera y relleno de tierra, suelo arenoso, alt. 10 m ;comun, 25 Oct. 1982, Koch & Fryxe1l82184 (holotype: CHAPA; isotypes: BH, BM, CTES, ENCB, F, MEXU, MICH, MO, NY, po. The specific epithet refers to the yellow center of the flower, which includes the claws of the petals, the staminal column, and the anthers, and which contrasts strikingly with the lavender blades of the petals.The species is most similar to K. blanchardii Fryx., which occurs at higher elevations (ca.1000 m).The new species also has a different leafform, a different type of pubescence, longer petioles, shorter pedicels, smaller involucels, calyces, and petals, no red border on the yellow claw, a yellow staminal column, shorter filaments, and smaller fruits.
Branched erect sub shrub 1-1.5 m tall, the stems hispidulous with hairs simple and ca.0.2 mm long or stellate and 0.5-1 mm long.Leaf blades triangular to hastately 3-10bed, the lower leaves to 8 cm long, progressively smaller upwards, more or less cordate at base, obscurely crenate to subentire, acute, discolorous (purplish above, greenish beneath), minutely and harshly stellate-hispid, more densely so beneath; petioles with pubescence like that of the stem, nearly equaling the leaf blade on larger leaves, progressively shorter than the blade upwards; stipules subulate, 3-5 mm long, inconspicuous.Flowers solitary in the axils (or sometimes paired with a subsidiary branch with several younger flower buds), the pedicel generally 2-3 cm long, antrorsely hispid, often purplish; calyx 8-10 mm long, broadly rounded, 7-8 mm broad basally, green (drying yellowish) but with 10 prominent purple nerves, stellate-pubescent, divided about halfway to base, the 5 lobes erect in flower, spreading in fruit, rounded-apiculate, red-orange (drying purplish) at apex; petals erect, narrowly spatulate, 15-20 mm long, 2-3 mm broad, orange-red becoming deep red, minutely stellate-pubescent on interior and exterior of the attenuate claw; staminal column up to 33 mm long (ca.twice length of petals), pallid, sparsely and minutely stellate-pubescent at base (and sometimes above), often glabrous distally; anthers borne at the apex of the column, ca.40, red (drying purplish), the filaments 2-3 mm long, the pollen yellowish; styles and stigmas ca.12-14, narrowly clavate, the tips purple.Fruits [immature] oblate, yellowish-hirsute; mericarps ca. 12, dorsally urn bonate.The specific epithet is chosen because of the superficial resemblance of the flowers to those of Lobelia lax iflora H.B.K.The flowers at anthesis are presented horizontally.They are evidently protandrous.The calyx and exserted staminal column are straight, but the petals are slightly displaced downward (this slight zygomorphy is not well preserved in pressed specimens).Thus, a hovering flower visitor approaching the flower from below would have its dorsal side dusted with pollen.The filaments are (at length) reflexed downward to make such pollen placement on a flower visitor more certain.The stigmas later occupy essentially the same position as the anthers.
Periptera lobelioides was observed only at the type locality on the northern slope of the Sierra Madre del Sur, on the opposite side of the divide (Puerto Balsamo?) from Vallecitos de Zaragoza, on the road from Zihuatanejo on the coast to Cuidad Altamirano.The plants were scattered over the grass-covered slopes.It apparently has its nearest affinity with P. trichostemon Bullock from Sinaloa, from which it differs by its longer petals, broader calyx, and more numerous carpels.
Herbs or sub shrubs to 1 m tall, the stems green, with stellate hairs 0.2--0.5 mm long and simple setae 1-2 mm long.Leaf blades lanceolate, to 8 cm long and 2 cm wide, broadest at base, truncate or subcordate, serrate to the base, acute, slightly discolorous, palmately 5-nerved, evenly and softly stellate-pubescent on lower surface with hairs 0.2--0.4mm long, with sparser and smaller hairs on upper surface; petioles up to 2.5 cm long, with pubescence similar to that of stem; stipules 4-8 mm long, filiform, ciliate.Pedicels solitary or in often unequal pairs in the leafaxils, up to 6 mm long, articulated 1-2 mm below flower, minutely pubescent; calyx (in fruit) 4-6 mm long, evenly and minutely stellate-pubescent; divided about halfway to the base, I O-ribbed at base; flowers (in anthesis) unknown.Fruits 4-5 mm in diam; mericarps 5, ca.5.5 mm long (including spines), the lower half indehiscent, broadly trigonal, glabrous, rugulose laterally and dorsally, the upper half dehiscent, minutely hispidulous, with two apical spines; spines ca.2.5 mm long with hairs becoming retrorse toward apex, diverging widely at maturity; seeds solitary.
The new species belongs in Sida section Cordifofiae (DC.) Fryx.(Fryxell 1985) on the basis of the retrorsely barbed spines of the mericarps.However, the 5-carpelled fruits and the spines retrorsely pubescent only toward the apex make it somewhat anomalous in this section.These differences notwithstanding, it is placed in section Cordifoliae, whose variation is correspondingly enlarged.The new species is readily distinguished from other species in the section by its 5-carpelled fruits , its long narrow leaves, and its frequently geminate (and sparse) flowers and fruits .The specific epithet is chosen with reference to the erect habit and handsome foliage of the new species.
Subshrubs I m tall, widely branched from the base, densely stellate-pubescent throughout, the stem hairs 0.4-0.9mm long.Leaf blades elliptic, up to 3.5 cm long and 2 cm wide (commonly shorter and narrower), 2-3 times as long as wide, truncate, serrate to the base, sometimes purplish-margined, acute to obtuse at apex; petioles 3-6(-15) mm long (ca.1/ 4-1 13 length of blade); stipules 4-7 mm long, filiform , prominently ciliate.Flowers 1-3 (usually unequally paired) in the leaf axils, aggregated into long dense racemiform branches with reduced leaves; pedicels up to 8 mm long, articulated ca. 2 mm below flower; calyx 6-7 mm long, divided about halfway to the base, the lobes acute, sometimes purplish-margined; corolla orange-yellow, sometimes with a red center.Fruits ca. 5 mm in diam; mericarps 8-9, 4-5 mm long (including spines), prominently rugulose laterally and dorsally in lower part with 4-6 winglike ridges along the juncture between the dorsal and lateral walls, laterally smooth in upper part, apically deshiscent and 2-spined; spines 1-2 mm long, retrorsely barbed, diverging at maturity at almost 90°; seeds solitary.Sida prolifica belongs in Sida section Cordifofiae (Fryxell 1985) and has its nearest affinity with S. salviifolia Presl.The mericarps of the two species are very similar in size and conformation (cf.Fryxell 1978, Fig. 1), except that those of S. prolifica are more coarsely rugulose with fewer and more prominent ridges along the angles.In addition, the two species differ in that S. prolifica is more densely pubescent, its hairs more than twice as long as those of S .salvii/olia.The leaves of S. proli/lca are shorter and broader, elliptic rather than narrowly ovate, and subacute to obtuse rather than acute.The stipules of S. proli/lca are narrower (filiform) and more prominently ciliate (hairs 0.5 mm long).In S. proli/lca the inflorescences are more crowded, with more numerous flowers and fruits (hence the specific epithet) than in S. salvii/olia.In some respects the new species is reminiscent of the Brazilian Sida cerradoensis Krapovickas, especially in its tendency toward purplish pigmentation in the calyx and leaf margins, but S. proli/lca differs in its shorter calyces, shorter mericarp spines, finer pubescence, and other characters.

HELICTERES REKOI Standley
Although this species is known from Jalisco to Oaxaca, as far as we are aware it has been collected no more than four times, and for this reason is poorly known (pers.comm.from C. Cristobal, who is revising the genus).The previous collections are: McVaugh 20997 (from Jalisco), Reko 3443 (the type, from Oaxaca), and Koch, Fryxell & Wendt 79531 (a topotype).Thus, a fourth collection from a new locality was a pleasant surprise.
The petals are large, fully reflexed, and bicolored, rose-colored on the distal part, white or cream-colored on the basal part.The exserted staminal column is also whitish.The white basal part of the corolla is more than half its length, its free petals forming a "throat."These details were not included in the original description by Standley for lack of suitable material.
Subshrub up to 0.5 m tall; stems greenish, slender, uniformly covered with a mixture of simple glandular hairs ca.0.5 mm long and smaller stellate hairs ca.0.2-0.4mm long, the latter sometimes with a central seta to 1 mm long or more.Leaf blades oblong or elliptic to narrowly ovate, basally truncate to acute, obscurely and coarsely crenate to subentire, apically acute to obtuse, up to 4 cm long and 1.5 cm wide, gradually reduced upwards, somewhat discolorous, with pinnate venation, evenly stellate-pubescent and with a few glandular hairs above and beneath, the stellate hairs on the upper surface often with a central, antrorsely oriented seta 0.5-1.5 mm long; petioles of larger leaves ca.0.5 cm long, with pubescence like that of stem, becoming shorter (leaves even subsessile) upwards.Fryxell 83 190)

Fig
Fig. I. Map of Mexico showing the approximate extent of the Sierra Madre del Sur (open circles) and the adjacent Balsas Depression (closed circles) (adapted fromRzedowski 1978, Fig. 4).Enlarged portions of Michoacan and Guerrero show localities referred to in text and in specimen citations.The "X" indicates the type locality for Piriquetia mexicana.