Ophioglossum vulgatum

Ophioglossum vulgatum L.
(Latin: vulgaris, common, commonplace, ordinary)

Local names: southern adder’s-tongue, adder’s-tongue

Similar to O. engelmannii; leaf (blade portion and fertile portion combined) 1 per stem; blade portion (2.5–) 5–10 cm long and 1.5–4(–5.5) cm wide, dark green, somewhat shiny, flat or nearly so when alive, apically rounded; fertile stalk 2–4 times as long as blade portion; sporangia 10–35 on each side of fertile stalk; “2n = ca. 1320” (Wagner & Wagner 1993), “2n = 960, about 1320” (Yatskievych 1999). Moist woods, meadows, swamps, usually in sandy soils; n Pineywoods, n Post Oak Savannah (e.g., Freestone Co., Carr & Singhurst 14452, TEX-LL; Leon Co., Carr 26629, TEX-LL), and w in Red River drainage to Fannin Co. (BRIT); also reported for the n Gulf Prairies and Marshes (Jefferson Co.—Correll 1956; but apparently based on a Mrs. J.L. Hooks s.n. collection of O. petiolatum at TEX-LL) and the Cross Timbers and Prairies (Denton Co.—Turner et al. 2003)—we have been unable to confirm the Denton and Jefferson collections and question their correctness— they are not mapped on the county distribution map; throughout most of the e U.S. w to IL, OK, and TX, also disjunct to s AZ (Wagner & Wagner 1993); also s Mexico and Eurasia. Leaves appearing spring to early summer; usually sporulating Mar–Jun. [O. pycnostichum (Fernald) A. Love & D. Love, O. vulgatum var. pycnostichum Fernald] Weakley (2010) and Peck (2011a) treated this species as O. pycnostichum, with Weakley (2010) noting, “O. vulgatum (defined narrowly) is Eurasian. The best treatment of this complex is uncertain.” As there is disagreement about appropriate nomenclature for this species, we are following Mickel and Smith (2004) in continuing to include the New World material in O. vulgatum. Wagner and Wagner (1993) pointed out shockingly high chromosome numbers, noting that in the Appalachian Mts. “a distinctive large-spored form has a chromosome number of 2n = ca. 1320.” This is primarily a species of the e ½ of the U.S. with a disjunct population in s AZ—this isolated occurrence is presumably the result of long-distance dispersal. Also see page 37 for a possible explanation of the disjunct distribution of this species from TX to s Mexico. Ophioglossum vulgatum can be confused with O. petiolatum but, in addition to the characters in the key, it has unusually persistent leathery basal leaf sheaths (these ephemeral in O. petiolatum) (Thomas 1979; Wagner & Wagner 1993).

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