Astrolepis integerrima

Astrolepis integerrima (Hook.) D.M. Benham & Windham
(Latin: integerrimus, very entire or whole, an emphatic assertion of the entirety of an organ)

Local names: hybrid scaly cloak fern, hybrid cloak fern, southwestern cloak fern, whole-leaf cloak fern

Plants morphologically heterogeneous; leaves 8–45 cm long; longest pinnae usually 7–12(–15) mm long, entire or shallowly asymmetrically lobed with 2–7 broadly rounded lobes, the lower surface completely concealed by scales, the upper surface densely scaly, particularly near margins, the scales usually persistent, elongate, stellate to coarsely ciliate; n = 2n = 87 (Benham & Windham 1993). Rocky slopes, outcrops, or cliffs, usually limestone or other calcareous substrates. Widely scattered in the w 2⁄3 of TX e to Palo Pinto, Burnet (Correll & Correll 12728), Starr (J. Ideker BA165) (all BRIT), Bell, Comal, Travis (TEX-LL), and Bexar (Turner et al. 2003) cos.; mostly sw U.S. (AZ, NM, NV, OK, and TX), and remotely disjunct to AL (J. Allison 6695, UNA, VDB; Allison 2001; Allison & Stevens 2001; in Bibb Co. on glades on an ancient [upper Cambrian] rock formation known as the Ketona Dolomite); also Mexico and the Carribean. Sporulating summer– fall. [Cheilanthes integerrima (Hook.) Mickel, Notholaena integerrima (Hook.) Hevly, Notholaena sinuate (Lag. ex Sw.) Kaulf. var. integerrima Hook.] Morphologically this variable species is somewhat intermediate between A. cochisensis and A. sinuate. However, it was hypothesized to be an apogamous triploid hybrid between A. cochisensis and an unnamed Mexican taxon related to A. crassifolia (of Mexico and Central America) (Benham 1989; Benham & Windham 1993). Subsequently, the “missing” parent was identified as Astrolepis obscura J. Beck & Windham (Beck et al. 2010). Recent research (Beck et al. 2011, 2012) has shown that A integerrima has multiple independent origins. In other words, this asexual taxon is an assemblage of many lineages that originated independently at least 10 different times from the same diploid ancestors (with four of the lineages occurring in TX). The morphological variability seen in A. integerrima is more understandable given its numerous independent origins. Beck et al. (2012) suggest that such multiple orgins may be the “rule, rather than the exception” among asexual polyploids and that the phenomenon warrants further study. Individuals with shallowly lobed leaves are superficially similar to A. windhamii, but can be distinguished by “the abundance and greater width of adaxial scales and the asymmetrical lobing of the pinnae.” Individuals with entire pinnae could be confused with A. cochisensis, but can be separated by the leaf blades with abundant basally attached scales on the upper surfaces and the larger pinnae (Benham & Windham 1993). This is one of a number of ferns found primarily in the sw or w U.S. with isolated disjunct populations in the southern Appalachians (see discussion on page 31). The population in AL is probably an excellent example of long-distance dispersal of spores.

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