Plants relatively robust, yellowish green, in dense tufts, rufous-tomentose proximally. Stems 1--3 (--6) cm, simple or forked. Leaves erect, straight or somewhat homomallous when dry, erect-spreading when moist, 1.2--2 mm, lanceolate acuminate; margins sharply serrulate, teeth paired but often appearing in groups of 3 or 4 because of strongly revolute margins; costa long-excurrent, scabrous abaxially distally; laminal cells strongly prorulose at distal ends, distal and median cells narrowly oblong, 18--35 × 3--5 µm, basal cells rectangular, 12--25 × 6--8 µm. Sexual condition dioicous. [Seta 1.5--2.5 cm. Capsule 1.5--2 mm. Spores subspherical to reniform, 23--26 µm, papillose.]

Open soils, road banks; 10--100 m; Ala., Fla. La.; Mexico; West Indies; Central America; n South America.

Philonotis sphaerocarpa is identified by the long-excurrent, scabrous costa, strongly revolute leaf margin, and leaf cells bearing prominent prorulae especially on adaxial side. While not uncommon in the tropical portion of its range, the species is relatively rare in the flora area.