16. Marathrum Humboldt & Bonpland
Marathrum Humboldt & Bonpland, Pl. Aequin. 1: 39. t. 11 (dated 1806, published 1808); van Royen, Meded. Bot. Mus. Herb. Rijksuniv. Utrecht 107: 70--91, 131--133 (1951), rev.
Roots thread-like and slightly flattened, branched; stems prostrate, flattened, often short and disk-like. Leaves arranged along lateral margins of prostrate stems; sheaths simple or double, sometimes elongated into stipules; petioles long, short or absent, terete or flattened; blades 1 or more times pinnate or entire in Marathrum utile Tulasne. Spathellas club-like or tubular. Flowers solitary or in fascicles of up to 5, arising from sheath pockets on stem; pedicels (0.5--) 1--9 cm long; tepals scale-like to filiform, 2--25, as many as or 1 more than stamens, in 1 complete or incomplete whorl, alternating with and more or less fused to base of stamen filaments; stamens 3--40 or more, in 1 or 2 whorls or confined to one side of flower; filaments linear to linear-lanceolate or triangular, sometimes united at base; pollen in monads. Capsules ellipsoidal, opening by 2 equal or subequal valves; each valve with 3 ribs, the ribs sometimes winged; pedicel in fruit expanded and cup-like at tip in some species; stigmas 2, linear to boat- or spoon-shaped, joined at base, often toothed at tip. Seeds ± 200--1500. About 25 spp. (probably less when critically examined), Mexico, C America, West Indies & northwestern South America.
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