Hypericum pleiostylum
Annual herb 0.10-0.26 m tall, erect or ascending from decumbent rooting base, with stems branched from or near the base, usually with up to 6 pairs branches above middle. Stems green to reddish-brown, 4-angled, sometimes ancipitous above, with lines smooth; internodes 8-25 mm, the uppermost not shorter, exceeding leaves. Leaves sessile, spreading, not tetrastichous, persistent; lamina 3-8 x 2-3.5 mm, ovate-deltoid to elliptic, plane, not cucullate, midrib prominent beneath, smooth, concolorous, glaucescent, membranous; apex rounded, margin plane, base rounded to cuneate, not sheathing, free; basal veins 3-5(-7), with less prominent midrib branches; tertiary reticulum dense, obscure; laminar glands rather dense, punctiform, prominent. Inflorescence 3-5(-7)-flowered, terminal, branching regularly dichasial/monochasial, sometimes with flowering branches from up to 3 nodes below, the whole fusiform-cylindric; pedicels c. 5 mm long; bracts foliar. Flowers c. 6-7 mm in diam., stellate. Sepals 2-2.5 x 0.5-1.2 mm, subequal to unequal, sometimes imbricate distally, obovate or oblanceolate to elliptic or narrowly oblong, apiculate-obtuse, veins 3, unbranched, not prominent; glands all or mostly linear. Petals golden (?) yellow, not veined red outside, 3-4 x 1-1.2 mm, c. 1.6-2 x sepals, oblong; apiculus and glands absent. Stamens 25-30, 5-fascicled or irregularly grouped, longest 1-1.5 mm long, c. 0.7 x petals. Ovary c. 1 x 0.6 mm, ovoid- ellipsoid; styles 5(6-8), c. 0.8 mm long, c. 0.8 x ovary; stigmas scarcely capitate. Capsule 2.5-3 x 2-2.5 m, broadly cylindric to globose, c. 1.5 x sepals. Seeds c. 0.7 mm long; testa finely and rather shallowly linear-scalariform.
'Campo'; lowland.
Brazil (Minas Geraes, Rio de Janeiro).
H. pleiostylum is clearly derived from the small-leaved Brazilian form of H. mutilum described by St.-Hilaire as H. euphorbioides, i.e. it is a neo-endemic. It differs from that form not only in the increased number of styles and ovary loculi (making the fruit globose rather than cylindric), but also in having an elongate terminal stem node (as in H. mutilum subsp. latisepalum) and foliar bracts (as in H. boreale and H. arenarioides). Rodriguez Jimenez (1973) queried the Rio de Janeiro locality, possibly because the localities on some other Glaziou labels have been shown to be unreliable (c.f. Wurdack, 1970).