Notholaena grayi Davenp. 1879

Introduction

Notholaena grayi is a typical member of core Notholaena I, with lanceolate leaf blades and scattered scales on the stalks. It occurs on a wide variety of rocky slopes and cliffs, in central and northern Mexico, and Arizona, New Mexico, and Texas (where it is rare to uncommon). It has two known cytotypes: some populations are diploid (two complete chromosome sets) whereas others are triploid (three complete sets). The diploid populations reproduce sexually and are recognized taxonomically as N. grayi subsp. sonorensis Windham (Diploid Gray’s Cloakfern). The triploid populations—N. grayi subsp. grayi (Triploid Gray’s Cloakfern)—reproduce apogamously (the sporophytes produce unreduced spores, which develop into triploid gametophytes, which then produce a new sporophyte directly from their vegetative tissue, without sexual reproduction; Windham, 1993a). The two cytotypes can only be distinguished by spore size and by spore number per sporangium. Notholaena grayi ssp. sonorensis is a taxon of southern Arizona and western Mexico; N. grayi ssp. grayi is more widespread.

Characteristics

With its whitish farina, lanceolate leaves, and scattered scales, N. grayi most closely resembles Argyrochosma pallens, Notholaena aliena, and N. schaffneri/N. nealleyi. Argyrochosma pallens has short-stalked pinnae (rather than sessile) and sporangia spread along the terminal portions of the veins (rather than confined to the very tips); N. aliena is very closely related to N. grayi but has long whitish hairs on the upper surfaces of its leaves; and N. schaffneri/N. nealleyi have darker leaf stalks, ciliate vs. short-toothed rhizome scales, and bristle-like vs. flat leaf scales (Mickel and Smith, 2004).

Other Names for Notholaena grayi Davenp. 1879

• Notholaena hypoleuca Kunze 1834
• Vernacular Names: Gray's Cloakfern, Diploid Gray's Cloakfern, Triploid Gray's Cloakfern

References

Giauque, M. F. A. 1949. Wax glands and prothallia. American Fern Journal 39:33-35.

Mickel, J. T., and A. R. Smith. 2004. The Pteridophytes of Mexico. The New York Botanical Garden Press, New York.

NatureServe. 2008. NatureServe Explorer, Arlington, Virginia. www.natureserve.org/explorer/

Rothfels, C. J., M. D. Windham, A. L. Grusz, G. J. Gastony, and K. M. Pryer. 2008. Toward a monophyletic Notholaena (Pteridaceae): Resolving patterns of evolutionary convergence in xeric-adapted ferns Taxon 57:712-724.

Tryon, R. M. 1956. A revision of the American species of Notholaena. Contributions from the Gray Herbarium 179:1-106.

Windham, M. D. 1993a. Notholaena. Pages 143--149 in Flora of North America (Flora of North American Editorial Committee, ed.) Oxford University Press, New York.

Windham, M. D., and G. Yatskievych. 2003. Chromosome studies of cheilanthoid ferns (Pteridaceae: Cheilanthoideae) from the western United States and Mexico. American Journal of Botany 90:1788-1800.

Wollenweber, E. 1984. Exudate flavonoids of Mexican ferns as chemotaxonomic markers. Rev. Latinoamer. Quim. 15:3-11.