Hypericum kalmianum (Nomenclature)
Shrub (0. 14-)0.2-0.6(-1) m tall, erect, with branches erect to ascending, forming slender to rounded or flat-topped bush. Stem green, 4-lined and ancipitous when young, soon 4-lined and rounded, becoming reddish brown and terete in 2nd season; cortex exfoliating in strips; bark smooth, thin. Leaves sessile, sometimes in immature clusters in leaf axils; lamina (15-)20-45 x 3-7(-10) mm, narrowly oblong to oblanceolate or linear, with margin subrecurved to revolute, paler or glaucous beneath, chartaceous, deciduous at basal articulation, apex rounded to obtuse or subapiculate-obtuse, base narrowly cuneate to subattenuate; venation rather obscure beneath: c. 9-14 pairs main laterals with subsidiaries and densely reticulate tertiaries, only midrib promi- nent; laminar glands dense. Inflorescence ( 1 )3-7(rarely more)- flowered, without accessory flowers, restricted to terminal node or rarely also from 1-2 nodes below; pedicels 2.5-7 mm long; bracts reduced, linear-oblong to oblanceolate. Flowers 20-35 mm in diam.; buds broadly ovoid. Sepals 5(4), 4-9 x 1.5-5 mm, enlarging and divergent to reflexed in fruit, imbricate, subequal to unequal (when 4), elliptic or oblong to obovate, obtuse or apiculate to acute, margins recurved to revolute, basal veins 3-7, branching and reticulating distally. Petals 5(4), golden yellow, becoming incurved-deflexed, 8-15 x 5-9(-12) mm, 1.6-2 x sepals, obovate to oblong, with apiculus lateral, rounded or obsolete. Stamens c. 150-200, longest 6-10 mm, 0.65-0.75 x petals. Ovary (3-4)5(6)-merous, 4-6 x 1.5-2 mm, narrowly ovoid, acute; placentation incompletely axile; styles (3-4)5(6), 3-4 mm long, 0.65-0.75 x ovary, remaining erect, separating only as fruit matures. Capsule 7-1 1 x 4-7 mm, narrowly ovoid-conic to narrowly cylindric-ellipsoid, obtuse, rounded or slightly lobed, longer than sepals, thinly coriaceous. Seeds purplish brown, 0.7-1.1 mm long, shallowly carinate; testa subscalariform.
2n = 18 (Hoar & Haertl, 1932; Pringle, 1976).
Dunes and sandy or calcareous rocky shores, sandy or calcareous plains and low prairies, along rivers and in Sphagnum-sedge swamps; c. 1 80-400 m.
U.S.A. and Canada adjacent to the Great Lakes and along the Ottawa River. The record (var. majus) for Tennessee (Coulter, 1886; Gattinger, 1887) is based on a mis-identification (see p. xx).
Despite its 5-merous ovary, H. kalmianum is clearly a northern derivative of H. prolificum, from which it differs in its shorter habit, its inflorescence usually being confined to the terminal node, and its usually 5-merous ovary. Adams (1962) thought that the presence of a 5-merous ovary in H. kalmianum and in 4. H. lobocarpum indicated that these species were closely related; but 5-mery in both species appears to be derivative. The fact that H. kalmianum is confined to once-glaciated areas (Utech & Iltis, 1970) supports the view that it is a relatively recent derivative of H. prolificum.