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Published In: Species Plantarum 1: 437. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

Project Name Data (Last Modified On 1/29/2015)
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Project Data     (Last Modified On 8/4/2009)


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4. Cerastium L. (mouse-ear chickweed)

Plants annual or perennial. Stems erect or ascending, often from spreading, somewhat matted, sprawling bases, often branched toward the tip, less commonly unbranched below the inflorescence, sparsely to densely pubescent with sometimes woolly hairs, some of the hairs sometimes gland-tipped. Leaves opposite, fused basally into a sheath, short-petiolate (basal leaves) or sessile and sometimes slightly clasping (stem leaves), in a few species with axillary clusters of leaves. Stipules absent. Leaf blades linear-lanceolate to oblong-spatulate or elliptic to broadly ovate, not fleshy, tapered at the base, angled to a bluntly or sharply pointed tip. Flowers in terminal open or relatively dense clusters or panicles, with stalks 0.1–2.5(–4.0) cm long, erect or ascending to somewhat spreading at flowering, sometimes appearing hooked or downward-angled at fruiting, the bracts paired and resembling small leaves, often with thin, whitened margins. Epicalyx absent. Sepals (4)5, usually fused at the base, the lobes narrowly elliptic to lanceolate or broadly lanceolate, green or sometimes reddish-tinged toward the tip, tapered or angled to a bluntly or more commonly sharply pointed tip, not appearing hooded or awned, the margins thin and white or translucent. Petals (4)5 or rarely absent, oblanceolate to spatulate, tapered to a stalklike base, shallowly notched or more commonly deeply 2-lobed (to about the petal midpoint) at the tip, white or rarely tinged with purple, lacking appendages. Stamens (4)5 or more commonly 10, the filaments distinct. Staminodes usually absent. Pistil with 1 locule, sessile. Styles (4)5 (rarely 3 elsewhere), distinct, each with a stigmatic area along the inner surface or subterminal. Fruits capsules, often curved, dehiscing apically by (8)10 (occasionally 6 elsewhere) erect to spreading, often somewhat inrolled teeth. Seeds 15–30 or more, wedge-shaped to kidney-shaped, the surface tuberculate or with minute papillae, orangish brown to brown, lacking wings or appendages. About 180 species, nearly worldwide, but most diverse in Europe and Asia, introduced nearly worldwide.

In addition to the ten species treated below, C. dubium (Bastard) Guépin (anomalous mouse-ear chickweed) should be expected in Missouri. First collected from eastern North America in central Illinois in 1980 (Shildneck and Jones, 1986), it is now known from at least one population in all states adjacent to Missouri except Iowa; those in Arkansas (Crittenden and Mississippi Counties; Rabeler, 1993) and Kansas (Labette County) are particularly close to our borders. Although the short, sparse glandular hairs on entirely herbaceous bracts would place C. dubium closest to C. nutans or C. brachypodum in the key below, C. dubium can be distinguished readily by its slender, almost linear leaves and shallowly notched petals. It also is distinct in having 3(4) styles and a straight (rather than curved) capsule that opens by 6(8) teeth.

Steyermark (1963) noted that the annual species of Cerastium sometimes are collected when young in the spring and cooked as vegetables.


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1 At least the upper inflorescence bracts with narrow to broad, thin, white to translucent margins (2)
+ All of the inflorescence bracts with green and herbaceous margins (thin and whitened at the very tip in C. diffusum) (6)
2 (1) Petals showy, 2–3 times as long as the sepals (3)
+ Petals shorter than to slightly longer than the sepals (4)
3 (2) Stems usually less than 20 cm long; sepal pubescence nonglandular; 1. Cerastium arvense subsp. strictum
+ Stems usually 20–40 cm long; sepal pubescence stipitate-glandular; 10. Cerastium velutinum var. velutinum
4 (2) Petals deeply lobed (often to the midpoint); sepals densely pubescent with usually nonglandular hairs, rarely some of the hairs stipitate-glandular; 5. Cerastium fontanum subsp. vulgare
+ Petals notched or shallowly lobed at the tip; sepals densely pubescent with stipitate-glandular hairs; stamens usually 5; fruits mostly straight, 4.0–7.5(–8.0) mm long (5)
5 (4) Bracts all with broad, thin, white to translucent margins (some-times the entire apical half thin and white to translucent); petal veins not branched; seed tubercles indistinct or low and rounded 9. Cerastium semidecandrum
+ Uppermost bracts with narrow, thin, white to translucent margins; petal veins branched; seed tubercles conspicuous, bluntly or sharply 8. Cerastium pumilum
6 (1) Pubescence nonglandular and sometimes also stipitate-glandular, that of the sepals extending beyond and somewhat obscuring the tip (7)
+ Pubescence glandular, that of the sepals not extending beyond the tip (8)
7 (6) Plants hairy, the hairs not long and silvery; flowers in a dense, crowded or slightly open cluster, the stalk shorter than the sepals 6. Cerastium glomeratum
+ Plants covered with long, silvery hairs; flowers in open panicles, the stalk 2. Cerastium brachypetalum
8 (6) Capsules about as long as to twice as long as the sepals; stamens 4 or 5; 4. Cerastium diffusum
+ Capsules twice as long or longer than the sepals; stamens 10; sepals with sparse, short glandular hairs (9)
9 (8) Flower stalks 2–5(–8) times as long as the sepals, at fruiting appearing 7. Cerastium nutans subsp. nutans
+ Flower stalks 1.0–1.5 times as long as the sepals, at fruiting not appearing hooked near the tip, but often downward-angled from the base 3. Cerastium brachypodum
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