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bulbous Adder's-tongue


Habit Plants terrestrial.

to 20 per plant, blackish, usually extremely narrow, often almost hairlike, less than 0.1 mm diam., proliferations not reported.

unbranched, whitish yellow to black, 0.1-1.5 mm diam., smooth, commonly proliferous and forming clones.


spheric, 3-12 mm diam., succulent, cormlike with perforation at apex, apical meristem located at bottom of cavity through which leaves emerge at top, leaves 2 per stem.

upright, forming caudex, to 1.6cm thick (cormlike in O. crotalophoroides);

gemmae absent.


brown to white, narrowly linear, unbranched, 2-20 × 1-3mm diam. x =30.


stalk to 0.6cm, 0.1-0.2 times as long as trophophore blade.;

trophophore blade lying nearly flat on ground, not folded longitudinally, pale green throughout, deltate to cordate, to 3 × 2 cm, contracted abruptly at truncate to cordate base, apex with apiculum.

erect to prostrate, blades nearly sessile or stalked, lanceolate to cordate, simple, 0.4-100 mm × 0.3-45 mm;

margins entire;

apex rounded, acute, or apiculate;

veins anastomosing, main areoles to 15 × 4mm, but mostly less than 5 × 3 mm.


coarsely reticulate with included veinlets.


arising at ground level, 1-5 times as long as trophophore;

sporangial clusters usually short, less than 1 cm, 2-3 mm wide, with 3-8 pairs of sporangia, apiculum to 1.5 mm.

1 per leaf, simple, stalked, borne from ground level to well above ground at base of trophophore but commonly absent, leaf made up of only trophophyll.


clusters with sporangia in 2 rows, deeply sunken in simple, linear or oblong fleshy sporophore tip, tip usually ± apiculate.

Ophioglossum crotalophoroides


Phenology Leaves appearing mainly in late winter and early spring, sometimes also appearing later in season after heavy rains.
Habitat Second-growth fields, vacant lots, roadside ditches, and lawns
Elevation 0-100 m (0-300 ft)
from FNA
AL; AR; FL; GA; LA; MO; MS; NC; SC; TX; Mexico; Central America; South America; widespread in tropical highlands; West Indies
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from USDA
Nearly worldwide; mainly tropical and subtropical
[BONAP county map]

Ophioglossum crotalophoroides is very remarkable morphologically for its highly modified stem and threadlike nonproliferous roots. The gametophyte is disclike (M.R. Mesler 1973). It is especially common in lawns and cemeteries in the southeastern United States.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Ophioglossum occurs mostly in disturbed, open, grassy habitats. It is often overlooked because of superficial resemblance to seedlings of monocotyledonous plants. The intensive and careful field studies of R.D. Thomas (W. H. Wagner Jr., C. M. Allen, and G. P. Landry 1984) have greatly extended our knowledge of adder's-tongue distributions in North America. The chromosome numbers of Ophioglossum are the highest known in all vascular plants; numbers as high as 2n =1200+ have been reported (A.Löve et al. 1977).

(Key to species of Ophioglossum)

Species 25-30 (7 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

1. Stems spheric, cormlike, fleshy, 3–12 mm diam.; leaves arising from deep cavity in top of stem; trophophore blades usually lying flat on ground, deltate to cordate.
O. crotalophoroides
1. Stems upright, 1–5 mm diam., seldom more; leaves arising at top of stem; trophophore blades erect to spreading, mostly ovate to lanceolate.
→ 2
2. Trophophore veins in larger leaves forming small areoles within larger areoles.
→ 3
2. Trophophore veins forming only branching or nonbranching, free, included veinlets within larger areoles.
→ 4
3. Blades commonly folded when alive, ovate to ovate-lanceolate, to 10 × 4.5 cm; roots 0.5–1.5 mm diam.; sporophores 1.3–2.5 times length of trophophore; dried blades uniformly green without pale central band.
O. engelmannii
3. Blades plane when alive, ovate to lanceolate, to 4.5 × 1.7 cm; roots 0.2–0.8 mm diam.; sporophores 2–6 times length of trophophore; dried blades commonly with pale central band.
O. nudicaule
4. Blades rounded at apex, apiculum absent, ovate-lanceolate, oblanceolate, ovate, to trowel-shaped, to 10 × 3.5 cm; adult leaves usually 1 per stem, appearing in a single flush once per year.
→ 5
4. Blades acute at apex, with ± developed apiculum or apiculum absent, ovate-oblong, ovate-deltate, or ovate-lanceolate, to 4.5 × 1 cm (6 × 3 mm occasionally in O. petiolatum); adult leaves commonly 2–3 per stem, appearing in 1 or more flushes per year, depending on rains.
→ 6
5. Blades dark green, somewhat shiny (alive), ovate to trowel-shaped, firm, base abruptly tapering; damp forest habitats; se United States, Mexican highlands.
O. vulgatum
5. Blades pale green, dull (alive), obovate to oblanceolate or ovate, herbaceous, base gradually tapering; open pastures, meadows, marshes, ditches; n North America.
O. pusillum
6. Roots dark brown, usually fewer than 8 per shoot, major roots generally straight, 0.8–1.3 mm diam.; blade apiculum mostly absent; venation usually coarse.
O. petiolatum
6. Roots yellowish to pale brown, usually more than 12 per shoot, 0.2–1 mm diam.; blade apiculum absent or present; venation usually fine, intricate.
→ 7
7. Roots 0.5–1 mm diam.; sporophores 1–2.5 times length of trophophore; trophophores 0.4–4.3 × 0.3–1 cm, commonly folded when alive; blades thick, herbaceous; California.
O. californicum
7. Roots 0.2–0.8 mm diam.; sporophores 2–6 times length of trophophore; trophophores as small as 0.4 × 0.3 cm, usually plane when alive; blades thin, herbaceous; se United States.
O. nudicaule
Source FNA vol. 2. FNA vol. 2.
Parent taxa Ophioglossaceae > Ophioglossum Ophioglossaceae
Sibling taxa
O. californicum, O. engelmannii, O. nudicaule, O. petiolatum, O. pusillum, O. vulgatum
Subordinate taxa
O. californicum, O. crotalophoroides, O. engelmannii, O. nudicaule, O. petiolatum, O. pusillum, O. vulgatum
Name authority Walter: Fl. Carol. 256. (1788) Linnaeus: Sp. Pl. 2: 1062. 1753; Gen. Pl. ed. 5, 484, (1754)
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