Least halberd fern

Aspidium fimbriatum Willdenow, Sp. Pl. 5(1): 213. 1810; A. minimum (L. Underwood) Clute; A. trifoliatum (Linnaeus) Swartz var. minimum Clute; Sagenia lobata C. Presl; Tectaria lobata (C. Presl) C. V. Morton; T. minima L. Underwood

Stems horizontal, short-creeping. Petiole straw-colored, 1--3 times length of blade, hairs absent abaxially, pubescent adaxially, base scaly; scales lanceolate to linear, 1--3 × 0.3--0.5 mm. Blade deltate to pentagonal, 1-pinnate or ternately lobed, 5--10 × 3--7 cm. Rachis and costae pubescent abaxially. Pinnae absent or 1(--2) pair, or blade shallowly pinnatifid, 4--7 cm, base rounded, without proliferous buds in axils. Areoles rarely with included veinlets. Indusia peltate. 2 n = 80.

Sinkholes, on shaded ledges or occasionally in sun; 0 m; Fla.; Mexico in Yucatán; West Indies in Bahamas, Greater Antilles.

The hybrid between Tectaria fimbriata and T . coriandrifolia is T . × amesiana A. A. Eaton. Although intermediate between the two parents, the hybrid will lead to T . fimbriata in the key. The hybrid may be distinguished from T . fimbriata by scattered hairs on abaxial surface of petioles and misshapen spores.