Astrolepis cochisensis

Astrolepis cochisensis (Goodd.)
D.M. Benham & Windham, (from the type locality in Cochise County, AZ)

Local names: Cochise scaly cloak fern, jimmy fern

Leaves 7–40 cm long; longest pinnae usually 4–7 mm long, entire or asymmetrically shallowly lobed with 1–4 broadly rounded lobes, the lower surface completely concealed by scales, the upper surface with scales sparse, deciduous, the scales mostly circular to slightly elongate, stellate to coarsely ciliate. Rocky slopes and cliffs usually on limestone; in TX mostly in Trans-Pecos (e.g., Brewster Co., Correll 14709, BRIT, TEX-LL), with a few localities in w Edwards Plateau (e.g., Uvalde Co., O.E. Sperry 3069, BRIT; Kimble Co., L.L. Hansen 4894, TEX-LL; Turner et al. 2003); AZ, CA, NM, OK, and TX; also n Mexico. Sporulating summer–fall. [Notholaena cochisensis Goodd., Cheilanthes cochisensis (Goodd.) Mickel, C. sinuate (Lag. ex Sw.) Domin var. cochisensis (Goodd.) Munz, Notholaena sinuate (Lag. ex Sw.) Kaulf. var. cochisensis (Goodd.) Weath.] Benham and Windham (1993) treated this species as being composed of three subspecies, two of which occur in TX (a sexual diploid and an apogamous triploid). They distinguished the three subspecies based on chromosome number, number of spores per sporangium, spore size, and the type of substrate the plants grow on. Mickel and Smith (2004) did not recognize the subspecies, merely viewing the different forms as cytotypes. We are continuing to follow Benham and Windham (1993) in recognizing the taxa at the subspecific rank because of their apparent reproductive isolation (based both on genetic and ecological isolating mechanisms). They separated the two TX taxa as in the following key. However, the two are not readily recognizable morphologically and are not distinguished on the county distribution map. The third subspecies (subsp. arizonica D.M. Benham, known only from AZ) is usually found on noncalcareous substrates and is an apogamous tetraploid, apparently with a complex origin possibly involving other taxa (Benham & Windham 1993). This species is known to be poisonous to livestock. An unidentified poison causes incoordination, arched back, rapid pulse, gasping, trembling (known as “the jimmies”), and prostration; in severe cases death can result from respiratory paralysis. Sheep are apparently most susceptible, followed by goats and cattle. A dosage of 0.8–3% of body weight for 2–3 days has been shown to be toxic. (Weathers 1998; Burrows & Tyrl 2001).

subsp. chihuahuensis D.M. Benham
(of Chihuahua, reflecting its distribution primarily in the Chihuahuan desert)

Local names: chihuahua scaly cloak fern

2n = 58 (Benham & Windham 1993). Rocky slopes and cliffs usually on limestone; this subspecies is mapped in Benham and Windham (1993) as occurring widely in the Trans-Pecos area; presumably most TX specimens of this species (which is widespread in Trans-Pecos, with a few localities in w Edwards Plateau) are of this subspecies (e.g., Brewster Co., Correll 13577; Hudspeth Co., Correll 15067; Pecos Co., McVaugh 7320, all TEX-LL, all annotated D.M. Benham); NM and TX; also ne Mexico. Sporulating summer–fall. This subspecies is reported to be a sexual diploid (Benham & Windham 1993). subsp. cochisensis, cochise scaly cloak fern. n = 2n = 87 (Benham & Windham 1993). Rocky slopes and cliffs usually on limestone; El Paso Co. (Correll 13832, 15039, TEX-LL, annotated D.M. Benham); Benham and Windham (1993) mapped this subspecies only in the extreme westernmost tip of the Trans-Pecos in the area of El Paso; AZ, CA, NM, OK (Panhandle), and TX; also n Mexico. Sporulating summer–fall. This subspecies is reported to be an apogamous triploid (Benham & Windham 1993). Because of its rareness and limited distribution in the state, we consider this subspecies to be of conservation concern in TX.

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