Polystemma fishbeiniana (Apocynaceae, Asclepiadoideae), a new species from the Balsas Depression of Michoacán, Mexico

keywords: biosphere reserve, endangered species, taxonomy, thorn forest, xeric scrub, Zicuirán-Infiernillo


Background: Polystemma (Apocynaceae subfamily Asclepiadoideae) is a small genus currently with seven species characterized by having white glandular trichomes becoming crystalline in age; filiform corona appendages; and fusiform, smooth, mottled follicles. Exploration in the Balsas Depression of Michoacán, Mexico resulted in the discovery of an unknown species of Polystemma.

Questions: Are the unknown Polystemma plants occurring in the Balsas Depression of Michoacán new to science? If so, how are they distinguished from other species of the genus, what are their ecological preferences, what is their distribution, and are they endangered?

Studied species: Species of Polystemma.

Study site and dates: Balsas Depression, Michoacán, México; 2001, 2003, 2004, 2014.

Methods: Fieldwork to collect herbarium specimens and photograph plants; review of literature on Polystemma to determine taxonomic status; preparation of a morphological description; evaluation of conservation status using IUCN Redlist criteria.

Results: Polystemma fishbeiniana is proposed as a new species and illustrated with photographs.  It occurs at two locations in the xeric scrub and open thorn forest of the Zicuirán-Infiernillo Biosphere Reserve, at elevations from 275 to 400 m.  Flowering occurs from June to September, with mature fruits present from October to March; dehisced fruits can persist on the plants for almost a year. Its conservation status is assessed as Endangered, EN B1ab(iii)+2ab(iii).

Conclusions: Polystemma fishbeiniana is distinguished from congeners by its suffrutescent habit, small leaves, and flowers abaxially yellowish with a blackish to dark burgundy red margin and central line with short lateral extensions.These traits are otherwise unknown in the genus.

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Author Biographies

Victor W. Steinmann, Universidad Autónoma de Querétaro, Facultad de Ciencias Naturales, Querétaro


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Warren D. Stevens, Missouri Botanical Garden, St. Louis, Missouri


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<em>Polystemma fishbeiniana</em> (Apocynaceae, Asclepiadoideae), a new species from the Balsas Depression of Michoacán, Mexico


Alvarado-Cárdenas LO, Lozada-Pérez L, Islas-Hernández SC, Cortez EB, Maya-Mandujano KG, Chávez-Hernández MG. 2020. Apocináceas de ayer y hoy. Conocimiento histórico y reevaluación de la diversidad y distribución de Apocynaceae en México. Botanical Sciences 98: 393-416. https://doi.org/10.17129/botsci.2525

Bachman S, Moat J, Hill AW, de la Torre J, Scott B. 2011. Supporting Red List threat assessments with GeoCAT: geospatial conservation assessment tool. In: Smith V, Penev L. eds. e-Infrastructures for data publishing in biodiversity science. ZooKeys 150: 117-126. https://doi.org/10.3897/zookeys.150.2109

Decaisne J. 1844. Asclepiadeae. In: De Candolle AP, ed. Prodromus Systematis Naturalis Regni Vegetabilis, Vol. 8. Paris: Masson, pp. 490-665.

Hernández Barón GM. 2021. Sistemática del género Polystemma (Gonolobinae, Apocynaceae). MSc. Thesis. Universidad de Guadalajara.

IUCN. 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Subcommittee. http://www.iucnredlist.org/documents/RedListGuidelines.pdf

Lot A, Chiang F. 1986. Manual de Herbario. Administración y Manejo de Colecciones. Técnicas de Recolección y Preparación de Ejemplares Botánicos. México: Consejo Nacional de la Flora de México. AC. ISBN: 9686144005

McDonnell A, Fishbein M. 2016. Polystemma canisferum (Apocynaceae, Asclepiadoideae): a distinctive new gonoloboid milkweed vine from Sonora, Mexico. Phytotaxa 246: 78-84. https://doi.org/10.11646/phytotaxa.246.1.6

Stevens WD. 2001. Asclepiadaceae. In: Stevens WD, Ulloa C, Pool A, Montiel OM, eds. Flora de Nicaragua. Vol. 1. St. Louis: Missouri Botanical Garden Press, pp. 234-270. ISBN: 9780915279951

Stevens WD. 2005. New and interesting milkweeds (Apocynaceae, Asclepiadoideae). Novon 15: 602-619. https://doi.org/10.2307/3393108

Thiers B. 2021. Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. http://sweetgum.nybg.org/science/ih (accessed July 2, 2021)

Woodson RE. 1941. The North American Asclepiadaceae I. Perspective of the genera. Annals of the Missouri Botanical Garden 28: 193¬–224. http://dx.doi.org/10.2307/2394270

How to Cite
Steinmann, V. W., & Stevens, W. D. (2022). Polystemma fishbeiniana (Apocynaceae, Asclepiadoideae), a new species from the Balsas Depression of Michoacán, Mexico. Botanical Sciences, 100(3), 759-764. https://doi.org/10.17129/botsci.2997