Pellaea atropurpurea

Pellaea atropurpurea (L.) Link
(Latin: atropurpureus, black-purple, = dark purple, in reference to the color of the petiole, which can be so dark as to appear almost black)

Local names: purple cliff-brake, purple-stem cliff-brake, cliff-brake, blue fern

Plant to 45(–50) cm tall; rhizome scales uniformly colored, reddish brown or tan; petioles dark reddish purple to nearly black, shiny; leaf blades usually 1-pinnate or 2-pinnate below, 10–30 cm long, 5–20 cm wide, somewhat dimorphic, the sterile ones shorter, less divided, and with relatively wider ultimate segments; rachis and costae densely pubescent on upper surfaces with short curly hairs; pinnae attached to rachis so that their tips point } straight out or somewhat towards tip of leaf, the basal pinnae mostly relatively longer-stalked (stalks 5–15 mm), the upper pinnae sessile or nearly so; ultimate leaf segments linear-oblong, apically obtuse to very slightly mucronate, leathery, often with a few hairs near midrib on lower surfaces; n = 2n = 87 (Windham 1993c). Rocky slopes and woods, cliffs, usually on limestone or calcareous rocks but also on igneous substrates; nearly throughout TX (e.g., Correll & Correll 12715, BRIT, TEX-LL); se Canada and most of the U.S. from VT s to FL w to MN, NV, and AZ; also Mexico and Guatemala. [Pteris atropurpurea (L.) Link, Pellaea atropurpurea var. cristata Trel.] Sporulating Mar–Nov. This species is a triploid that reproduces via apogamy (= a type of asexual reproduction that does not involve gamete formation or fertilization; this type of reproduction allows triploids, which would otherwise produce sterile spores and be sterile, to make fertile spores and thus reproduce) (Tryon 1972). Its origin is unclear; Windham (1993c) suggested that “it appears that P. atropurpurea is an autopolyploid derivative of a single diploid taxon that has not yet been located.” Pellaea atropurpurea “is possibly the most widely distributed fern in Texas, growing in many areas where rock outcrops appear” (Yarborough & Powell 2002). Tryon (1972) pointed out that the purple cliff-brake “is the only American species of the large complex of cheilanthoid ferns that has a range extending from the tropics into northern regions, including New England.”

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