Asplenium septentrionale

Asplenium septentrionale (L.) Hoffm.
(Latin: septentrionalis, north or northern, in the type description Linnaeus mentioning its citation in his Flora Lapponica and Flora Suecica)

Local names: forked spleenwort, northern spleenwort

Rhizomes erect, much branched; leaves usually numerous, densely tufted, monomorphic, often simple or 1-pinnate (perhaps better described as forked) with only 2–3(–5) strongly ascending pinnae, to only ca. 15 cm tall; leaf blades linear; petioles much longer than blades, dark reddish brown, becoming green distally; rachises green; pinnae linear, 3 cm or less long, 3 mm or less wide, often curved, basally and apically acute, marginally entire or with a few teeth near apex, glabrous; sori 2–3 per pinna, very elongate; 2n = 144 (Wagner et al. 1993). Rock crevices and ledges on noncalcareous rocks; in TX known only from one collection at 7,000 ft elevation at Boot Springs in Chisos Mts., Brewster Co. (J.L. Blassingame 1043, Jun 1969, HPC, OKLA, xerox SRSC; Correll & Johnston 1970); in North America primarily in the Rocky Mts. from NM n to UT and WY, with scattered localities in AZ, CA, CO, OK, OR, SD, TX, UT, and WY and disjunct e to isolated populations in AR (3000 ft., Mt. Magazine—J.H. Peck, pers. comm.), WV (Emory 1970; Bush 1986), and D.C.; also nw Mexico, Europe and Asia. ?–Jun–Jul–?. [Acrostichum septentrionale L.] The isolated Monroe and Hardy county WV populations represent a disjunction of about 700 mi (1,127 km) to the e of the single AR location and that AR population is more than 500 mi (800 km) e of the nearest station in w OK and about 700 mi (1,127 km) nw of the lone TX site (Emory 1970; Wagner 1972; Bush 1986; Wagner et al. 1993; J.H. Peck, pers. comm.). It 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). This species has a widespread overall distribution in the northern hemisphere (also in Europe and Asia), possibly the result of vicariance (remnants of a past more continuous distribution that has become fragmented) or of long-distance dispersal (Holderegger & Schneller 1994; Weber 2003). Forked spleenwort resembles a tuft of grass and is thus easily overlooked in the field. Hybrids with A. trichomanes (A. ×alternifolium Wulfen) are known (Wagner et al. 1993). Given its rareness and limited distribution in the state, we consider this species to be of conservation concern in TX.

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