A new species of Sicyos L. (Cucurbitaceae) from Oaxaca, Mexico ISELA RODRI´GUEZ-ARE´VALO, RAFAEL LIRA, ISMAEL CALZADA
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Rodrı´guez-Are´valo, I.*, R. Lira & I. Calzada (Unidad de Biotecnologı´a y Prototipos, Universidad Nacional Auto´noma de Me´xico, Campus Iztacala, Avenida de los Barrios s.n. Los Reyes lztacala, Tlalnepantla, Estado de Me´xico, C.P. 54090, Me´xico; e-mail*:
[email protected]). A new species of Sicyos L. (Cucurbitaceae) from Oaxaca, Mexico. Brittonia 57: 43–46. 2005.—Sicyos mcvaughii, a new species from Oaxaca, is described and illustrated. It is similar to Sicyos sertuliferus Cogn., and grows in secondary tropical deciduous forest, between 20 and 630 meters. Key words: Cucurbitaceae, Mexico, Oaxaca, Sicyos.
The Cucurbitaceae are represented in Mexico by 141 species and subspecific taxa (Lira et al., 2002), grouped into two subfamilies and 34 genera. The genus Sicyos is one of the most diverse within the family. In his most recent classification, Jeffrey (1990) placed Sicyos in subfamily Cucurbitoideae, tribe Sicyeae, subtribe Sicyinae (along with Sicyosperma, Parasicyos, Microsechium, Sechium, Sechiopsis, and Pterosicyos). According to Jeffrey (1990), Sicyos consists of ca. 40 species. In the last five years a revision of Mexican Sicyos has been accomplished (Rodrı´guez-Are´valo, 2001). As a result of this revision, five new species have been described (Lira & Rodrı´guez-Are´valo, 1999; Rodrı´guez-Are´valo & Lira, 2001; Rodrı´guez-Are´valo, 2003; Rodrı´guez-Are´valo et al., 2004). We are herein proposing an additional new species from Oaxaca, which raises the number of species of Sicyos known from Mexico to 17. Sicyos mcvaughii Rodrı´guez-Are´valo, Lira & Calzada, sp. nov. (Fig. 1) T YPE : MEXICO. Chiapas: Municipio Santa Marı´a Huatulco, en la desviacio´n a Huatulco, carretera Salina Cruz-Puerto Angel, 15846.7909N, 96809.3319W, 62 m, 12
Nov 1999, I. Rodrı´guez-Are´valo & J. I. Calzada 297 (HOLOTYPE: MEXU; ISOTYPES: ENCB, IEB, IZTA, MICH, MO, NY, XAL). Herba repens vel scandens. Folia ovato-triangularia valde acuminata. Flores staminati 5-meri, antheris exsertis. Flores pistillati 5–7-meri, stigmate exserto 3– 4-lobo, lobis rotundatis vel ovoideis, reflexis. Sicyo sertulifero similis, sed fructibus siccis triangulari-ovoideis, spinis caducis differt.
Scandent monoecious herb, creeping and climbing by tendrils; stems slender, branched, sulcate, glabrous to sparsely villous at the nodes. Leaves simple, thin, membranous to papyraceous, broadly ovate-triangular, 5–7-angulate-lobed, 3.5– 17 3 3.3–19.6 cm, the lobes wide, triangular, the central lobe longer than the lateral, strongly acuminate, the margin serrulate-denticulate, both surfaces strigose, abaxial surface with the veins more prominent and the trichomes shorter; petioles 0.7–6 cm long, sulcate, sparsely to densely glandular-villous; tendrils long-stalked, 2.6–10 cm long, sulcate, 3–6-branched, sparsely to densely glandular-villous. Staminate inflorescence in the same axil as the pistillate, panicles, racemes of umbels, or a combination of both, 7.6–40.5 cm long, erect; peduncle 6.2–22.7 cm long; rachis densely glandular-pubescent toward the apex; pedicels slender, 2.9–10.6 mm long, ascendant,
Brittonia, 57(1), 2005, pp. 43–46. q 2005, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A.
ISSUED: 31 March 2005
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FIG. 1. Sicyos mcvaughii. A. Habit. B. Staminate flower. C. Pistillate flower. D. Fruit (Rodrı´guez-Are´valo & Calzada 297, MEXU)
2005] COMPARISON
´ VALO ET AL.: SICYOS (CUCURBITACEAE) RODRI´GUEZ-ARE TABLE I OF THE MORPHOLOGICAL CHARACTERISTICS OF
Characteristics
Staminate inflorescence Stigma Fruit
Fruit armature
Sicyos mcvaughii
Acicular, antrorse, retrorsely barbed, all caducous
Additional specimens examined. MEXICO. OAXAMpio. Santiago Astata, Distrito de Tehuantepec, Istmo, por Pie del Cerro, 2 km al NE de Barra de la
AND
Sicyos sertuliferus
Sicyos sertuliferus
Panicles, racemes of umbels or a combination of both 3–4-lobed, the lobes rounded to ovoid Dry, triangular-ovoid, slightly rostrate, 0.8–1 cm long, 0.3–0.6 cm in diameter, densely armed
densely glandular-pubescent villous; flower receptacle 5-merous, narrowly campanulate, 0.6–2 mm long, 0.8–3 mm wide; calyx lobes subulate, 0.2–0.4 mm long; corolla greenish yellow, 5-merous, the lobes triangular, 1–3 3 0.5–2 mm, the margins and adaxial surface densely glandular-villous; stamens fused into a column 2.5–4.7 mm long, the filaments forming a central column, the anthers united forming a globose head, the thecae curved. Pistillate inflorescence umbelliform; peduncle 1–2.2 cm long, elongating to 5.5 cm in fruit, densely glandular-villous. Pistillate flowers numerous; ovary unilocular, ovoid, slightly rostrate, armed, densely glandular-pubescent villous; ovule 1, occupying almost the entire locule; receptacle and perianth smaller than those of the staminate flowers; corolla with 5–7 petals; column of style and stigma 2.5 mm long; stigmas conspicuously exserted, 3–4-lobed, the lobes rounded to ovoid, reflexed. Fruits numerous, dry, 0.8– 1 cm long, 0.3–0.6 cm in diameter, triangular-ovoid, slightly rostrate, densely armed except for the rostrum; fruit wall thin, strongly attached to the seed, light to dark brownish; spines 2–6.3 mm long, acicular, antrorse, caducous, retrorsely barbed, yellowish. Seed ovoid, compressed, dark brown. present, Sicyos Distribution. At mcvaughii has been collected only in Oaxaca, Mexico, in secondary tropical deciduous forest, at elevations between 20 and 630 meters. CA.
Sicyos mcvaughii
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Racemes of umbels 3–lobed, the lobes triangular Dry, ovoid, 0.8–1.4 cm long, 0.2–0.6 cm in diameter, with some verrucose, antrorse projections mainly at the base, glabrous Acicular, antrorse, retrorsely barbed, some caducous and some persistent
Cruz, 158159140N, 958579550W, 20 m, 31 Oct 1998, M. Elorsa 1021 (MEXU); Mpio. San Miguel del Puerto, Distrito de Pochutla, San Isidro Chacalapa, 3.5 km N por brecha hacia Chongo, paso el rı´o Chacalapa, 158579040N, 958569400W, 230 m, 25 Oct 1999, C. Perret et al. 671 (MEXU); Zimata´n, 7 km por la carretera a Huatulco, desviacio´n de la Garza, 158489540N, 968029030W, 30 m, 23 Oct 1999, J. Rivera et al. 2013 (MEXU); Km 234 de la carretera Huatulco-Pochutla, 15845.2709N, 96817.3419W, 74 m, 12 Nov 1999, I. Rodrı´guez-Are´valo & J. I. Calzada 298 (MEXU); La Merced del Potrero, 4 km S, 3.8 km de la brecha, camino al Colorado Grande, 168009290N, 968049490W, 630 m, 28 Oct 1999, S. Salas et al. 2510 (MEXU).
Sicyos mcvaughii is closely related to S. sertuliferus Cogn., with which it shares exserted stamens and stigmas, and similar ovoid fruits. Nevertheless, S. mcvaughii can be distinguished from S. sertuliferus by its staminate inflorescences, which consist of panicles, racemes of umbels, or a combination of both, its rounded to ovoid stigma lobes, and its caducous fruit armature. In contrast, S. sertuliferus has staminate inflorescences grouped exclusively in racemes of umbels, triangular stigmatic lobes, and a combination of caducous and persistent spines on the fruit. In addition the two species have different distributions: S. mcvaughii has been collected only in Oaxaca, whereas S. sertuliferus is known from Costa Rica and along the Pacific Coast of Mexico in the states of Colima, Guerrero, Jalisco, and Michoacan. Morphological differences between the species are summarized in Table I. The new species is named in honor of Dr. Rogers McVaugh (b. 1909), who has contributed immensely to knowledge of the Mexican flora.
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Acknowledgments We wish to thank Dr. Fernando Chiang (MEXU), who prepared the Latin description and made comments on the manuscript. The illustration of Sicyos mcvaughii was made by Jesu´s Moctezuma Garcı´a. Funds for this research were provided to the first author by the Consejo Nacional para la Ciencia y la Tecnologı´a (CONACyT), through the master’s thesis scholarship CONACyT-92140. Literature Cited Jeffrey, C. 1990. Appendix: an outline classification of the Cucurbitaceae. Pages 449–463. In: D. M. Bates, R. W. Robinson & C. Jeffrey, editors. Biology and utilization of the Cucurbitaceae. Cornell University Press, Ithaca, New York.
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Lira, R. & I. Rodrı´guez-Are´valo. 1999. Nuevas especies de los ge´neros Cyclanthera Schrad. y Sicyos L. (Sicyeae, Cucurbitaceae) para la flora de Me´xico. Acta Bot. Mexicana. 48: 11–19. ———, J. L. Villasen˜or & E. Ortiz. 2002. A proposal for the conservation of the family Cucurbitaceae in Mexico. Biodiversity and Conservation 11: 1699–1720. Rodrı´guez-Are´valo, I. 2001. Revisio´n del ge´nero Sicyos L. (Cucurbitaceae) en Me´xico. Tesis de Maestrı´a. Facultad de Ciencias, Universidad Nacional Auto´noma de Me´xico, Me´xico, D.F. ———. 2003. A new species of Sicyos (Cucurbitaceae, Sicyeae, Sicyinae) from Mexico and Guatemala. Brittonia 55(1): 69–72. ——— & R. Lira. 2001. Nueva especie del ge´nero Sicyos L. (Cucurbitaceae) para la Repu´blica Mexicana. Bol. Soc. Bot. Me´xico 68: 81–84. ———, ———, & P. Da´vila. 2004. Two new species of Sicyos L. (Cucurbitaceae) from Guerrero and Oaxaca, Mexico. Bot. J. Linn. Soc. 145: 373–378.
