Hypericum tenuifolium

Hypericum tenuifolium
Photo by Keith Bradley, Atlas of Florida Vascular Plants
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida - Dicotyledons
Order:	Theales
Family:	Clusiaceae ⁄ Guttiferae
Genus:	Hypericum
Species:	H. tenuifolium
Binomial name
Hypericum tenuifolium Pursh
Natural range of Hypericum tenuifolium from USDA NRCS Plants Database.

Common name: Atlantic St. John's-wort; Sandhill St. John's-wort

Taxonomic notes

Synonyms: Hypericum reductum (Svenson) W.P. Adams; H. aspalathoides Willdenow.

Varieties: none.

Description

H. tenuifolium is a short-lived perennial herb that can reach heights of 12 to 18 inches. Stems are reddish-brown and are covered with short needle-like shiny, deep-green leaves. The flowers have 5 yellow petals, 5 persistent sepals, a superior ovary, and are bisexual and radially symmetrical. A distinctive characteristic of this species is a long seed capsule, ranging from 6 to 9 mm long.

“Usually glabrous herbs or shrubs. Leaves usually punctate, simple, opposite, entire, usually sessile or subsessile, exstipulate. Inflorescence basically cymose; flowers perfect, regular, bracteates, subsessile or short-pedicellate, sepals 2, 4, or 5, persistent; petals 4 or 5, usually marcescent, yellow or pink; stamens 5-numerous, separate or connate basally forming 3-5 clusters or fascicles, filaments usually persistent; carpels 2-5, stigmas and styles separate or fused, ovary superior, 1-locular or partly or wholly 2-5 locular, placentation axile or parietal. Capsules basically ovoid, longitudinally dehiscent, styles usually persistent; seeds numerous, lustrous, areolate, cylindric, or oblong. In general, our species form a polymorphic complex with many intergrading taxa.”

"Decumbent, matted shrub, 1-5 dm tall, stems usually angled. Leaves linear-subulate, the largest 5-13 mm long, 0.5-1 mm wide, acute, slightly revolute, base notched, sessile. Cymules or dichasia terminal and axillary, or flower solitary, axillary. Sepals 5, similar to leaves, usually less than4.5 mm long; petals 5, 4-10 mm long; styles 3, united or usually separate in fruit, 0.8-3 mm long, ovary 3-locular. Capsules subcylindric, 6-9 mm long, 1.5-2 mm broad; seeds blackish, ca. 0.5 mm long."

Distribution

This plant occurs from southeastern North Carolina to southern peninsular Florida, as well as throughout the Florida Panhandle and southeastern Alabama.

Ecology

Habitat

This species is found in dry, sandy, open sites with good drainage such as sandy woods, dunes and dune hollows, lowland, and coastal areas. It is drought tolerant, however, it does not favor well in soils that remain wet for extended periods. Associated species include Polygonella polygama, Pinus palustris, and Paronychia chartacea.

Phenology

Flowering occurs during late spring and early summer with more than a dozen flowers open at any time. Flowers are yellow and aromatic with the fruit capsule ranging from 6 to 9 mm in length.

Pollination and use by animals

Various species were observed to visit the flowers of Hypericum tenuifolium at the Archbold Biological Station. These species include long-tongued bees from the Apidae family (Apis mellifera, Bombus griseocollis and B. impatiens), plasterer bees from the Colletidae family (Colletes distinctus, C. productus and Hylaeus confluens), sweat bees from the Halictidae family (Augochlorella aurata, A. gratiosa, Augochloropsis anonyma, A. metallica, A. sumptuosa, Lasioglossum miniatulus, L. nymphalis, L. placidensis and L. tamiamensis), and leafcutting bees from the Megachilidae family (Anthidiellum perplexum, Dianthidium floridiense, Megachile albitarsis, M. brevis pseudobrevis and M. rugifrons).