Hypericum collinum (Nomenclature)
Wiry perennial herb (0.25–)0.3–0.5 m tall, erect, sometimes from decumbent and rooting base, branched above with branches divergent to ascending. Stems 2-lined and ancipitous above, terete below, turning vinous red, eglandular; internodes 10–30 mm, exceeding leaves. Leaves sessile or to 1.5 mm petiolate: lamina 6–20 × 2–9 mm, elliptic-oblong to oblanceolate, paler beneath, chartaceous; apex rounded to retuse, margin plane, base cuneate to angustate; venation: 2–3 pairs of main laterals from lower quarter to half of midrib, tertiary reticulation dense, more visible beneath; laminar glands pale, dense, varying in size; intramarginal glands black, dense. Inflorescence (1)3–c. 20-flowered, from 1–2 nodes, lax, with branches from up to 5 nodes below, the whole subcorymbiform to broadly pyramidal; pedicels 1–9 mm; bracts foliose, bracteoles 3–4 mm long, oblanceolate, entire, often subopposite or alternate. Flowers c. 10 mm in diam., stellate; buds cylindric, rounded, red-veined. Sepals 5, unequal, free, (2.5–)3–4 × 0.8–1.5 mm, lanceolate to oblong or oblanceolate, apiculate-obtuse to rounded, entire or rarely subentire; veins 3–5, outer branching and anastomosing; laminar glands all pale or rarely a few black, linear and distally punctiform; marginal glands black, few, intramarginal to very rarely prominent, or absent. Petals 5, yellow, 5–7 × 2–3 mm, 1.7–2 × sepals, obovate-oblanceolate, rounded, entire or almost so; laminar glands pale, linear to striiform; marginal glands black, numerous, sessile or subsessile. Stamens c. 20–25, ‘3’-fascicled, longest 4.5–5.5 mm, c. 0.8 × petals; anther gland black. Ovary 1.5–2 × 0.8 mm, narrowly ovoid; styles 3, 1.8–2.2 mm, 1.2 × ovary, divergent; stigmas narrowly capitate. Capsule 7 × 3 mm, narrowly ovoid-cylindric, longitudinally vittate. Seeds dark brown, 0.4–0.5 mm long; testa densely reticulate-scalariform.
Dry gravelly banks; 1500–2100 m.
Mexico (Veracruz, Oaxaca, Puebla, Hidalgo).
Hypericum collinum is apparently derived from 2a. H. oaxacanum subsp. veracrucense and approaches specimens of the latter from Chiapas most closely. It differs in its small, usually shortly petiolate leaves and its smaller flowers with unequal, obtuse to rounded sepals and shorter styles. The sepal characters also serve to distinguish it from 4. H. epigeium, as well as the different habit and terete stems.