Flora of North America species comparison

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Hypericum tenuifolium

Atlantic St. John's-wort
Habit Shrubs, usually decumbent, not rooting, forming mats, 1–5 dm.
Stems

internodes 6-lined at first, becoming 4-lined, then terete.
Leaf

blades linear-subulate, 4–11 × 0.4–0.8 mm, base articulated, persistent, parallel or slightly expanded, margins revolute, apex rounded with ± prominent hydathode to long-acuminate, midrib unbranched.
Inflorescences

± narrowly cylindric, 1–7-flowered, with 1(–3)-flowered dichasia from to 4 proximal nodes, rarely with 1 pair of flowering branches;

flowers sessile or nearly so.
Flowers

10–14 mm diam.;

sepals deciduous, not enclosing capsule, 5, linear-subulate, unequal, 2–4 × 0.4–0.5 mm;

petals 5, bright yellow, oblanceolate-oblong to obovate, 5–10 mm;

stamens deciduous, 50–90;

ovary 3-merous.
Capsules

narrowly (sub-)cylindric, (4–)5.7–9.5 × 1.5–2 mm.
Seeds

scarcely carinate, 0.5 mm;

testa coarsely reticulate.
2n

= 18.

Hypericum tenuifolium
Phenology Flowering spring–mid summer (Apr–Jul).
Habitat Dry, sandy woods, dunes and dune hollows, coastal plain
Elevation 0–200 m (0–700 ft)
Distribution
from FNA
AL; FL; GA; NC; SC
[WildflowerSearch map]
[BONAP county map]
Discussion

Hypericum tenuifolium differs from H. galioides in habit, leaf size, and inflorescence, and in its drier habitat. Its nonrooting stems, longer leaves, and (usually) longer stems distinguish it from H. lloydii.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 6, p. 79.
Parent taxa Hypericaceae > Hypericum > sect. Myriandra
Sibling taxa
H. adpressum, H. anagalloides, H. apocynifolium, H. ascyron, H. boreale, H. brachyphyllum, H. buckleyi, H. canadense, H. canariense, H. chapmanii, H. cistifolium, H. concinnum, H. crux-andreae, H. cumulicola, H. densiflorum, H. denticulatum, H. dolabriforme, H. drummondii, H. edisonianum, H. ellipticum, H. erythreae, H. fasciculatum, H. frondosum, H. galioides, H. gentianoides, H. graveolens, H. gymnanthum, H. harperi, H. hypericoides, H. kalmianum, H. lissophloeus, H. lloydii, H. lobocarpum, H. maculatum, H. majus, H. microsepalum, H. mutilum, H. myrtifolium, H. nitidum, H. nudiflorum, H. paucifolium, H. perforatum, H. prolificum, H. pseudomaculatum, H. punctatum, H. radfordiorum, H. scouleri, H. setosum, H. sphaerocarpum, H. suffruticosum, H. tetrapetalum, H. virgatum, H. ×mitchellianum
Synonyms H. fasciculatum var. laxifolium, H. reductum
Name authority Pursh: Fl. Amer. Sept. 2: 377. (1813)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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