Cerastium texanum |
Cerastium aleuticum |
|
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Chihuahuan mouse-ear chickweed, Texas chickweed, Texas mouse-ear chickweed |
Aleutian chickweed, Aleutian mouse-ear chickweed |
|
Habit | Plants annual, with slender taproot and branched caudex. | Plants perennial, tufted, rhizoma-tous, eglandular. |
Stems | erect, sparingly branched proximally, slender, 15–35 cm, sparsely glandular-pilose; small axillary tufts of leaves absent. |
branched, 3–7 cm, subglabrous proximally, softly pubescent distally, proximal internodes congested; small axillary tufts of leaves absent. |
Leaves | not marcescent; proximal blades broadly spatulate-petiolate, 8–55 × 3–16 mm, apex acute or obtuse, sometimes short-acuminate, softly pilose; cauline few, sessile, blade linear-lanceolate to narrowly oblanceolate, 7–30 mm, apex acute, pilose. |
proximal leaves marcescent, pseudopetiolate, spatulate, distal sessile; blade elliptic to lanceolate or oblanceolate, 4–12 × 2–5 mm, apex ± obtuse, hirsute with long, straight, eglandular hairs or subglabrous except for midrib and margins. |
Inflorescences | very open and loose, 2–9(–25)-flowered cymes; bracts narrowly lanceolate, pilose. |
1–3-flowered, dense cymes; bracts foliaceous, margins not scarious, pubescent. |
Pedicels | straight, becoming sharply deflexed at base, slender, 5–20 mm, elongating in fruit, 1.5–4 times as long as sepals, glandular-pilose. |
becoming curved at apex, slender, 2–12 mm, to 3 times as long as sepals, pubescence spreading, eglandular, fuscous hairs equaling or longer than pedicel diam. |
Flowers | sepals green, turning pale orange-brown in fruit, lanceolate to ovate, 3–6 mm, margins narrow, apex acute, with short, glandular pubescence; petals oblanceolate, 5–8 mm, 1.5–2 times as long as sepals, apex 2-fid; stamens 5; styles 5. |
sepals lanceolate to elliptic, concave, 4–5 mm, margins narrow, apex acute to obtuse, pubescent; petals 1–1.5 times as long as sepals, apex 2-fid; stamens 10; styles 5. |
Capsules | cylindric, straight, 5–12 mm, 1.5–2 times as long as sepals; teeth 10, becoming outwardly coiled. |
cylindric, slightly curved, 8–11 mm, 1–2 times as long as sepals, teeth 10, ± erect, margins convolute. |
Seeds | red-brown, 0.4–0.7 mm diam., tuberculate; tubercles ± pointed; testa not inflated. |
brown, 0.8–1 mm, shallowly and obtusely tuberculate; testa not inflated, tightly enclosing seed. |
2n | = 36. |
|
Cerastium texanum |
Cerastium aleuticum |
|
Phenology | Flowering spring. | Flowering summer. |
Habitat | Canyons, sandy washes, oak woodlands, mountain pine forests | Stony ground, screes, etc., mountain slopes |
Elevation | 1200-2800 m (3900-9200 ft) | 200-700 m (700-2300 ft) |
Distribution |
AZ; NM; Mexico
|
AK |
Discussion | Cerastium texanum is exceptionally variable in flower and capsule size. The extent to which this variation is due to environmental conditions or is genic in origin is not known. The broad, spatulate basal leaves and the straight, cylindric capsule with its outwardly coiled (revolute) teeth distinguish this species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cerastium aleuticum is an eglandular relative of C. beeringianum. It is similar to C. bialynickii except in being eglandular and having less dense pubescence and narrower sepals. It is confined to the western arctic, mainly on the Aleutian, St. Lawrence, St. Paul, Popof, and Kodiak islands, but is not found on mainland Alaska. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 90. | FNA vol. 5, p. 77. |
Parent taxa | Caryophyllaceae > subfam. Alsinoideae > Cerastium | Caryophyllaceae > subfam. Alsinoideae > Cerastium |
Sibling taxa | ||
Synonyms | C. longepedunculatum var. sordidum, C. sordidum, Stellaria montana | C. beeringianum var. aleuticum |
Name authority | Britton: Bull. Torrey Bot. Club 15: 97. (1888) | Hultén: Svensk Bot. Tidskr. 30: 520, figs. 3a,b. (1936) |
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