Notholaena candida (M. Martens & Galeotti) Hook. 1864

Introduction

Notholaena candida, a species of limestone or igneous cliffs and outcrops, is widespread in Mexico and extends southward to Costa Rica. It has attractive triangular-to-pentagonalish glabrous leaves, and is thus a well-behaved member of the core Notholaena II clade. Notholaena candida is here treated in a restricted sense; N. copelandii is treated separately. The two taxa are often lumped (N. copelandii as N. candida var. copelandii), based primarily on a number of intermediate specimens from San Luis Potosí (Tryon, 1956). Those specimens aside, however, the two taxa show strong morphological differences, geographic isolation, different farina chemistry (Wollenweber, 1984), and significant DNA sequence divergence (Rothfels et al., 2008). I thus follow recent authors (Mickel and Smith, 2004; Windham, 1993a) in treating them as distinct species.

Mickel and Smith (2004) report specimens of N. candida with light yellow farina instead of the typical white; these individuals deserve further attention.

Characteristics

Notholaena candida is most likely to be confused not with another Notholaena, but rather with Cheilanthes farinosa. The Costa Rican specimens, for example, were long identified as Cheilanthes farinosa prior to the recognition of their true identity. The two species can be extremely similar in leaf shape, farina color (white), habit, and habitat, but the Cheilanthes has a very strongly differentiated paper-like false indusium, which the Notholaena lacks. See the N. copelandii page for morphological features distinguishing it from N. candida.

Other Names for Notholaena candida (M. Martens & Galeotti) Hook. 1864

• Notholaena revoluta A. Rojas 2006
• Vernacular Names: Quartz Cloakfern

References

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

Hall, C. C. 1950. Notholaena copelandii, a newly recognized species of the Texano-Mexican region. American Fern Journal 40:178--187.

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.

Wollenweber, E., M. Dörr, and J. F. Stevens. 2001. A dihydroflavonol with taxonomic significance from the fern Notholaena sulphurea. Zeitschrift für Naturforschung 56:499-502.