Ophioglossum engelmannii Prantl
Family: Ophioglossaceae
limestone adderstongue,  more...
[Ophioglossum engelmanii Prantl]
Ophioglossum engelmannii image
(c) 2004 Steven J. Baskauf  
Roots to 25 per plant, tan to brown, 0.5-1.5mm diam., straight, producing proliferations. Stem upright, to 1.5 cm, 4 mm diam., leaves 1-2 per stem. Trophophore stalk to 0.1 cm, 0.01 times length of blade. Trophophore blade erect to spreading, commonly ± folded when alive, uniformly pale green throughout when dried, dull, ovate to ovate-lanceolate, 10 × 4.5 cm, firm, herbaceous, base narrowed abruptly, apex with apiculum to 0.8 mm; venation complex-reticulate, veinlets forming numerous, very tiny, secondary areoles within the major areoles. Sporophores arising at ground level, 1.3-2.5 times as long as trophophore; sporangial clusters 2-4 × 0.13-0.31 cm, pairs of sporangia 20-40, apiculum 0-1.3 mm. Leaves appearing early-late spring, often with second flush later in season following summer rains. Mostly in soil over limestone in open fields, pastures, and cedar glades; 50-1000 m; Ala., Ariz., Ark., Fla., Ga., Ill., Ind., Kans., Ky., La., Miss., Mo., Ohio, Okla., N.Mex., N.C., Tenn., Tex., Va., W.Va.; Mexico; Central America.
Bases of old lvs persisting on the rhizomes; lvs often 2 or more, the blade usually somewhat trough-shaped in life, acute at each end, apiculate, the veins forming areoles that enclose many smaller areoles and also some free veinlets; otherwise much like O. vulgatum. Woods, pastures, and ledges, mostly in calcareous soils; nw. Va. to s. Ill. and e. Kans., s. to Fla., Ariz., and Mex. Spr.-early summer.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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