Hypericum cumulicola
Hypericum densiflorum
highlands scrub hypericum, highlands scrub St. Johnswort
bushy St. John's-wort, dense St. Johnswort
internodes 4-lined.
internodes 4-lined at first, soon 2-lined to terete.
appressed, sessile;
blade linear-subulate, (1–)2.5–4 × 0.2–0.3 mm, subcoriaceous, margins incurved, apex acute, basal vein 1, midrib unbranched.
blades narrowly elliptic-oblong or oblanceolate to linear, 20–45 × 2–7 mm, base articulated, narrowly cuneate to attenuate, margins recurved to revolute, apex apiculate-rounded to subacute, midrib with 14–17 pairs of branches.
subcorymbiform, to 13-flowered, branching mostly dichasial.
broadly pyramidal to broadly cylindric, 5–25-flowered from apical node, with (2–)5–15-flowered dichasia from 1–2 proximal nodes.
3–4 mm diam.;
sepals ovate to elliptic or narrowly oblong, unequal, 1.5–2 × 0.6–1 mm, margins sometimes ciliate, not setulose-ciliate, apex acute to subacute;
petals yellow, obovate-oblong, 3.5–5 mm;
stamens 20–25, irregularly arranged;
styles 1.5–2 mm;
stigmas capitate.
10–17(–20) mm diam.;
sepals deciduous, not enclosing capsule, 5, narrowly oblong to oblanceolate-spatulate, unequal or subequal, 4–6 × 1–1.5 mm, basal veins 1–3;
petals 5, deep golden yellow, obovate-oblanceolate, 6–9 mm;
stamens deciduous, 100–150;
ovary 3–4(–5)-merous.
narrowly ovoid-conic, subrostrate, 3.5–6 × 1–1.5 mm.
narrowly ovoid conic to cylindric-ovoid, 5–6(–7) × 2–3 mm, not or scarcely lobed.
0.5–0.6 mm;
testa scalariform-reticulate.
not carinate, 0.8–1.3 mm;
testa linear-reticulate.
= 12.
= 18.
Hypericum cumulicola
Hypericum densiflorum
Of conservation concern.
Hypericum cumulicola is confined to Highlands and Polk counties and its habitat is under threat from bulldozers and citrus groves (D. B. Ward 1980); its nearest relative, with the same chromosome number, appears to be H. setosum.
Hypericum cumulicola is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Hybrid intermediates between Hypericum densiflorum and H. lobocarpum occur in northwestern Alabama, and a narrow-leaved, small-flowered form in Tennessee and northern Georgia (H. interior) verges toward H. galioides. Hypericum densiflorum is always distinct from H. prolificum in the wild; these species hybridize in gardens. Hypericum ×arnoldianum Rehder, known in cultivation only, was thought by Rehder to have the parentage H. galioides × lobocarpum; on both morphological and cytological grounds, the conclusion of W. P. Adams (1972) that it was H. densiflorum × lobocarpum seems much more likely.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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