Plants winter annual or annual. Taproots filiform. Stems erect to ascending, green, 5-30 cm, glabrous or sometimes stipitate-glandular distally or throughout, internodes of all stems 1-7 times as long as leaves; wintering stems absent. Leaves overlapping proximally, connate proximally, with loose, scarious to herbaceous sheath 0.1-0.5 mm; blade straight to variously curved, green, flat, prominently 1-veined abaxially, linear, 2-20 × 0.5-1.5(-1.8) mm, flexuous, margins not thickened, herbaceous, smooth, apex green or purple, blunt to acute, flat, ± shiny, glabrous to stipitate-glandular; axillary leaves absent. Inflorescences 5-30-flowered, open cymes; bracts subulate to ovate, herbaceous. Pedicels 0.3-3 cm, stipitate-glandular. Flowers: hypanthium shallowly disc-shaped; sepals prominently (3- or) 5-veined, narrowly to broadly lanceolate (herbaceous portion narrowly to broadly lanceolate), 4-5.5 mm, not enlarging in fruit, apex green or purple, narrowly acute to acuminate, not hooded, glabrous to sparsely stipitate-glandular; petals obovate, 1.5-2.2(-3) times as long as sepals, apex rounded, broadly notched. Capsules on stipe ca. 0.1 mm or shorter, narrowly ellipsoid, 3-4.2 mm, shorter than sepals. Seeds reddish brown to black, suborbiculate, radicle obscure, slightly compressed, 0.5-0.6 mm, tuberculate; tubercles low, rounded.
Flowering spring-early summer. Prairies, meadows, limestone barrens, and rocky outcrops in sandy, clayey, or gravelly soils; 0-500; Ala., Ark., Ga., Ill., Ind., Kans., Ky., La., Miss., Mo., Ohio, Okla., Pa., Tenn., Tex., Va., Wis.
Minuartia patula and the related M. muscorum have received little attention in comparison to the granite-outcrop minuartias, the M. uniflora complex. J. A. Steyermark (1941) studied these taxa and described three forms, based chiefly on pubescence variation. Plants entirely glabrous [forma pitcheri (Nuttall) Steyermark] and those with sepals and pedicels somewhat stipitate-glandular (forma media Steyermark) were segregated from densely stipitate-glandular plants (forma patula). We do not feel that such variations deserve formal taxonomic recognition. Forma robusta, as defined by Steyermark, is here referred to M. muscorum.
Most specimens of Minuartia patula have prominently five-veined sepals (seen especially easily in the glabrous forms); occasional plants from Georgia, Kentucky, and Virginia have glabrous sepals with only three strong veins, resembling those of M. muscorum; in other features, including the seeds, they are clearly referable to M. patula. The status of the plants with three-veined sepals remains ambiguous; J. A. Steyermark (1941) included them in his forma media and B. Maguire (1951) included them (in our opinion incorrectly) in his var. robusta.
On wooded gravelly slopes along streams and in shallow soil on sandstone bluffs. Local but very common in some of its stations.
Annual herb with a taproot 10 - 30 cm tall
Stem: upright to ascending or decumbent, slender, much branched at base, sometimes minutely glandular-hairy.
Leaves: opposite, stalkless, 0.5 - 2 cm long, 0.5 - 1 mm wide, linear to thread-shaped with a blunt to pointed tip, prominently one-veined, fleshy.
Inflorescence: an open, hairy-branched cluster (cyme) of five to thirty flowers on a 1.5 - 3 cm long stalk.
Flowers: white. Stalk 0.3 - 3 cm long, glandular-hairy. Stamens ten. Styles three.
Sepals: five, 4.5 - 6 mm long, lance-shaped with a pointed tip, prominently three- to five-veined, sometimes sparsely glandular-hairy.
Petals: five, white, 5 - 8 mm long, reverse egg-shaped with a rounded tip, broadly notched.
Fruit: a dehiscent capsule (opening by six teeth), short-stalked, 3 - 4 mm long, equal to or shorter than the sepals, narrowly ellipsoid. Seeds reddish brown to black.
Similar species: The linear to thread-shaped leaves (usually under 2 mm wide) help distinguish this species and Arenaria stricta from all other Arenaria in the Chicago Region. Arenaria stricta differs by having mostly flat, linear to bristle-like leaves and hairless inflorescence branches.
Flowering: May to early July
Habitat and ecology: Very local to sometimes abundant, especially where limestone beds are near the surface of the ground.
Occurence in the Chicago region: native
Etymology: Arenaria comes from the Latin word arena, meaning sand, referring to the fact that most species in this genus prefer sandy habitats. Patula means spreading.
Author: The Morton Arboretum
Annual, usually much-branched at base, glabrous or minutely glandular- puberulent; stems slender, 1-2 dm, decumbent or erect; lvs mostly cauline, several pairs, 1-2 cm נ0.5-1 mm; infl open, often extending to below the middle; pedicels 15-30 mm; sep 4.5-6 mm, narrowly lanceolate, acute; pet white, 5-8 mm; fr equaling or shorter than the sep, lance-oblong, the 3 valves dehiscent to the middle; seeds gray-brown, low-tuberculate. Apr.-June. (Minuartia p.) Var. patula, occurring in rocky soil, barrens, and meadows, from Ind. and Minn. to Va., Ala., and Tex., has 5-nerved sep, and the seeds are 0.5-0.7 mm. Var. robusta (Steyerm.) Maguire, occurring on limestone slopes in Mo., Ky., and Tenn., has 3-nerved sep, and the seeds are 0.7-0.9 mm.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
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