Cerastium fontanum |
Cerastium regelii |
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common chickweed, common mouse-ear chickweed, céraiste commun, mouse-ear chickweed |
céraiste de Regel, Regel's chickweed, Regel's mouse-ear chickweed |
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Habit | Plants perennial (rarely annual), tufted to mat-forming, often rhizomatous. | Plants perennial, highly variable, ranging from small, pulvinate, 1–6(–8) cm, often not flowering, to rhizomatous. | ||||
Stems | flowering stems erect from decumbent base, branched proximally, 10–45 cm, softly pubescent, eglandular with straight hairs; nonflowering shoots, when present, produced proximally, decumbent, rooting at nodes, branched, 5–20 cm, often subglabrous with alternating lines of eglandular hairs; small axillary tufts of leaves usually absent. |
erect or trailing, branched, pubescence confined to alternating lines of short, crispate to more elongate hairs; flowering stems erect, 1–6(–8) cm in pulvinate plants, to 20 cm in creeping plants, pubescence spreading to retrorse; nonflowering shoots creeping, elongate, 1–30 cm, with terminal, fleshy, gemmaelike buds; small axillary tufts of leaves absent. |
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Leaves | not marcescent; blade 10–25(–40) × 3–8(–12) mm, densely covered with patent to ascending, colorless, long, eglandular hairs; leaves of flowering shoots in distant pairs, sessile, blade elliptic to ovate-oblong, apex subacute; leaves of sterile shoots pseudopetiolate, often spatulate, blade oblanceolate, apex obtuse. |
sessile; blade rotund and obovate to ovate, elliptic, or broadly lanceolate, 3–9 × 2–6 mm, succulent, apex ± acute to obtuse; proximal leaves connate at base, blades becoming marcescent, broadly and shortly spatulate, margins and midrib ciliate, glabrous to sparsely pubescent, hairs long, colorless. |
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Inflorescences | lax, 3–50-flowered cymes; bracts lanceolate, reduced, herbaceous, eglandular-pubescent, distal often with narrow, scarious margins. |
erect, lax, 1–5(–11)-flowered cymes; bracts elliptic to lanceolate, with or without narrow, scarious margins, with long, strigose hairs. |
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Pedicels | somewhat curved distally, 2–10(–20) mm, longer than sepals, densely pubescent with patent, eglandular, rarely glandular hairs. |
erect, usually straight, 1–10(–30) mm, shorter than sepals in pulvinate plants, longer in creeping plants, softly pubescent, hairs patent, of varying lengths, glandular and eglandular. |
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Flowers | sepals ovate-lanceolate, 5–7 mm, margins narrow, apex acute, scarious, pubescent with eglandular, rarely glandular, hairs; petals oblanceolate, 1–1.5 times as long as sepals, apex deeply 2-fid; stamens 10, occasionally 5; styles 5. |
sepals often purple tinged, broadly elliptic, 4–6 mm, margins broad, apex round, obtuse, sparsely pubescent, hairs colorless, long, eglandular, and short, glandular; petals obovate, 4–8 mm, 1.5–2 times as long as sepals, apex deeply 2-fid; stamens 10; styles 5. |
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Capsules | narrowly cylindric, curved, 9–17 mm, ca. 2 times sepals; teeth 10, erect, margins convolute. |
cylindric, slightly curved, 6–12 mm, 1–2 times as long as sepals; teeth 10, erect to slightly spreading, margins convolute. |
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Seeds | reddish brown, 0.4–1.2 mm, bluntly tuberculate; testa not inflated, tightly enclosing seed. |
dark brown, 1 mm diam., shallowly tuberculate; testa not inflated, tightly enclosing seed. |
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2n | = 122–152, usually 144. |
= 72. |
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Cerastium fontanum |
Cerastium regelii |
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Phenology | Flowering summer. | |||||
Habitat | High-arctic tundra to low-arctic taiga, often in wet solifluction areas or in moss | |||||
Elevation | 0-900 m (0-3000 ft) | |||||
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NS; NT; ON; PE; QC; SK; YT; Europe [Introduced elsewhere]
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AK; NT; NU; QC; Greenland; nw Europe (Spitsbergen); Asia (Russian Far East, Siberia) |
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Discussion | Subspecies 4 (2 in the flora). Cerastium fontanum is a highly variable and complex species. It often has been reported as C. vulgatum Linnaeus, an ambiguous name; see discussion under the genus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Until recently, Cerastium gorodkovianum (= C. jenisejense) was recognized as a species separate from C. regelii, the former being low arctic and the latter high arctic. A recent experimental study by O. M. Heide et al. (1990) elegantly demonstrated that the morphological differences are the result of the effects of day length and temperature on development. In the high arctic, C. regelii rarely flowers and is compact and pulvinate with small, broadly obovate, marcescent leaves that are fleshy, subglabrous, or with strigose cilia. In the low arctic and taiga zone, C. regelii becomes a slender, straggling plant with slender, erect inflorescences bearing a few large flowers. The creeping sterile shoots produce terminal bulbils for vegetative dispersal. Apparent hybrids between Cerastium regelii and C. beeringianum were named C. regelii var. hirsutum Hultén. An apparent hybrid with C. arvense subsp. strictum also has been collected along the Nisling River in the Yukon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5. | FNA vol. 5, p. 89. | ||||
Parent taxa | Caryophyllaceae > subfam. Alsinoideae > Cerastium | Caryophyllaceae > subfam. Alsinoideae > Cerastium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | C. alpinum var. caespitosum, C. gorodkovianum, C. jenisejense, C. regelii subsp. caespitosum | |||||
Name authority | Baumgarten: Enum. Stirp. Transsilv. 1: 425. (1816) | Ostenfeld: Skr. Vidensk.-Selsk. Christiana, Math.-Naturvidensk. Kl. 1909(8): 10, fig. 11. (1910) | ||||
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