Cerastium alpinum |
Cerastium brachypodum |
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alpine chickweed, alpine mouse-ear chickweed, céraiste alpin |
bractpod chickweed, mouse-ear chickweed, short-stalk mouse-ear chickweed, shortstalk chickweed |
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Habit | Plants perennial, mat-forming, rhizomatous. | Plants annual, with filiform tap-root. | ||||
Stems | prostrate or ascending, tomentose (very rarely subglabrous), hairs white, translucent, long, soft, flexuous, some usually also short and glandular; flowering shoots ascending, 5–20 cm; small axillary tufts of leaves usually absent; nonflowering shoots ± prostrate, to 6 cm. |
erect, simple or several from branched caudex, 5–20 cm, glandular-pubescent, nodes without long, wooly hairs; small axillary tufts of leaves absent. |
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Leaves | marcescent or not, sessile; blade obovate or ovate to elliptic-oblanceolate, elliptic, or lanceolate, usually 10–18 × 5–7 mm, apex obtuse, pubescence as on stems. |
sessile, not marcescent, usually confined to proximal 1/2 of plant; mid-stem leaves with blade lanceolate to narrowly elliptic or oblanceolate, 5–30 × 2–8 mm, apex ± acute, usually rather sparsely, softly pubescent; proximal leaves sometimes forming loose rosette, blade ovate to obovate or spatulate, apex ± obtuse. |
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Inflorescences | open, (1–)2–4-flowered cymes; bracts lanceolate, acute, margins narrow, scarious, glandular-pubescent. |
compact to open, dichotomous, 3–30-flowered cymes, confined to distal portion of stem; bracts herbaceous, lanceolate, glandular-puberulent. |
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Pedicels | straight but often becoming angled at base and curved at apex, slender, 5–30 mm, often elongating to 3 or 4 times as long as sepals, pubescence usually dense, hairs both long, flexuous, multicellular, and short, glandular, viscid. |
often becoming deflexed at base, 3–10(–12) mm, 0.5–1.25 times as long as sepals in flower, elongating to equaling capsule, glandular-pubescent. |
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Flowers | sepals green, often violet tipped, narrowly elliptic-lanceolate, 7.5–10 mm, margins ± narrow, apex acute to obtuse, densely pubescent, hairs both long, eglandular and short, glandular; petals 1–2 times as long as sepals, apex shallowly 2-fid; stamens 10; styles 5. |
sepals broadly lanceolate, 3–4.5 mm, apex subacute, glandular-puberulent to glabrate, hairs shorter than sepal tip, outer sepals herbaceous or with narrow margins, inner with broad margins; petals ovate-elliptic, 3–4 mm, equaling or shorter than sepals, apex 2-fid; stamens 10; styles 5. |
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Capsules | cylindric, slightly curved, 12–16 mm, to 2 times as long as sepals; teeth 10, erect, margins convolute. |
cylindric, curved, 6–12 mm, 2–2.25 times as long as sepals; teeth 10, erect, margins convolute. |
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Seeds | dark brown, 1–1.4 mm diam., acutely tuberculate; testa not inflated. |
golden brown, 0.4–0.7 mm diam., tuberculate, especially around edge; testa not inflated. |
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2n | = 72, 108. |
= 34. |
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Cerastium alpinum |
Cerastium brachypodum |
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Phenology | Flowering spring and early summer. | |||||
Habitat | Grasslands, fields, meadows, open woods, roadsides, waste places, often in seasonally wet rocky or sandy ground | |||||
Elevation | 100-2700 m (300-8900 ft) | |||||
Distribution |
MB; NT; NU; ON; QC; SK; Canada; Greenland; Europe (Iceland, Scandinavia)
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AL; AR; AZ; CO; GA; IA; ID; IL; IN; KS; LA; MI; MO; MT; ND; NE; NM; NV; OK; OR; SC; SD; TN; TX; UT; VA; WI; WY; AB; MB; ON; SK; Mexico
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Discussion | Subspecies 3+ (2 in the flora). The Cerastium alpinum group of species is a difficult complex of intergrading taxa. E. Hultén (1956) considered this complex to be the result of worldwide introgression among the various taxa. Members of this group in North America include C. aleuticum, C. alpinum, C. arcticum, C. beeringianum, C. bialynickii, C. fischerianum, C. regelii, and C. terrae-novae. Cerastium alpinum itself is distinguished from all other members of the complex by its lanate pubescence, which consists of long, silvery, translucent, multicellular, flexuous, often tangled hairs; the more or less square base of the calyx; the convex margins of the sepals; and, in well-grown plants, the long, slender, divaricate pedicels. In western North America, Cerastium alpinum is replaced by C. beeringianum, which has long, straight, strigose, somewhat fuscous hairs, usually smaller flowers, and smaller seeds. The two species intergrade in eastern Canada; intermediate specimens were named C. alpinum var. strigosum Hultén. Cerastium arcticum differs from C. alpinum, with which it often grows, in its straight, somewhat fuscous hairs; calyx which is round at the base; long, narrowly lanceolate sepals; large, straight, broad capsules; and broad, obtuse cauline leaves. Like C. alpinum, it usually has large flowers with the petals much longer than the sepals. Many infraspecific taxa have been named in Cerastium alpinum but in North America it is much less variable than elsewhere. Two forms can be recognized at either the varietal or subspecific level. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cerastium brachypodum differs from C. nutans in its smaller size; its short pedicels, which often become deflexed at the base instead of near the capsule; and its pubescence, which is usually sparser and lacks any long, lanate hairs. However, some specimens from the arid region of the southwest have a dense gray pubescence. Plants from the Arizona desert, which have particularly long and narrow capsules, are the basis for the erroneous report of C. gracile Dufour from that region. Cerastium fastigiatum can be very similar to C. brachypodum but differs in its longer pedicels, narrowly acute leaves, glandular pubescence on the stems, and much more branched (fastigiate) habit. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 5, p. 77. | FNA vol. 5, p. 83. | ||||
Parent taxa | Caryophyllaceae > subfam. Alsinoideae > Cerastium | Caryophyllaceae > subfam. Alsinoideae > Cerastium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | C. nutans var. brachypodum, C. adsurgens, C. brachypodum var. compactum | |||||
Name authority | Linnaeus: Sp. Pl. 1: 438. (1753) | (Engelm. ex A. Gray) B. L. Rob.: Mem. Torrey Bot. Club 5(Sig. 10): 150. 27 Apr (1894) | ||||
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