Psilotrichum sericeum Dalzell

Erect or occasionally prostrate or ascending annual herb, ± 0.3–1 m. tall, much branched in the lower half and frequently also above, the lowest internodes of particularly the lower branches very divergent.. Stem and branches striate, the lower internodes terete, the upper subquadrate and ± sulcate, nodes somewhat swollen; indumentum very variable, from subglabrous or with sparse soft pubescence to dense with a double indumentum of shorter soft hairs and long fine multicellular spreading bristly hairs (even when absent elsewhere tufts of bristly hairs occur between the branches and leaves at least of the upper nodes, frequently forming a ring there).. Main stem and branch leaves cordate-ovate to broadly ovate or rarely cordate-lanceolate, obtuse to acuminate at the apex, 1.3–7 × 0.7–5.2 cm., the lowest on petioles up to ± 1(–1.8) cm. long, leaves towards the ends of the stem and branches reducing in size and sessile; indumentum very variable, from green on both surfaces (moderately softly appressed pilose below and thinly so with long and shorter multicellular strigose hairs above) to moderately appressed pilose above and densely silvery sericeous on the lower surface.. Inflorescence a large open compound panicle of axillary opposite panicles formed of simple or branched spikes, each with a flexuose glabrous rhachis; peduncle and branches of the partial inflorescences capillary, glabrous or with long strigose multicellular hairs; bracts lanceolate, 0.75–1 mm., sparingly pilose, mucronate with the excurrent midrib; bracteoles similar but slightly shorter.. Flower sessile.. Tepals green, acute, prominently 3-nerved with the nerves confluent at the apex and excurrent in a minute mucro, glabrous or usually ± furnished with spreading white multicellular minutely denticulate hairs; 2 outer 2–2.5 mm., narrowly hyaline-margined with all 3 nerves equally strong, if hairs present then all nerves white pilose, hairs sometimes also present on the surface between; inner 2 widely hyaline-margined (the margin wider than the nerved central portion at halfway up the tepal), pilose only along the midrib, which is much stronger than the lateral nerves; middle tepal with one side as in the outer 2 and one as in the inner 2.. Stamens delicate, ± 1.5–1.75 mm., pseudostaminodes none.. Style short, ± 0.5 mm.. Capsule ovoid, ± 1.75–2 mm.. Seed subglobose, black, shining, feebly reticulate, ± 1.5 mm.. Fig. 21/1–6.

It is a tropical plant.