Cerastium texanum |
Cerastium axillare |
|
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Chihuahuan mouse-ear chickweed, Texas chickweed, Texas mouse-ear chickweed |
Trans Pecos mouse-ear chickweed, trans-Pecos chickweed |
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Habit | Plants annual, with slender taproot and branched caudex. | Plants annual, viscid. |
Stems | erect, sparingly branched proximally, slender, 15–35 cm, sparsely glandular-pilose; small axillary tufts of leaves absent. |
usually erect, simple or several-branched, from branched caudex, rarely bushy, 6–40 cm, glandular-pilose, hairs in mid-stem region equaling or longer than stem diam.; small axillary tufts of leaves absent Leaves sessile; blade 7–25 × 1–6 mm; basal rosette absent or poorly developed and withering when young; proximal with blade oblanceolate to spatulate; distal with blade linear-lanceolate or lanceolate to narrowly elliptic, apex usually acute, rarely obtuse, glandular-pilose. |
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. |
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Inflorescences | very open and loose, 2–9(–25)-flowered cymes; bracts narrowly lanceolate, pilose. |
diffuse, elongate, usually with single dichotomy at or below mid stem, 3–18-flowered cymes, glandular-pubescent, flowers widely and racemosely spaced in axils of paired bracts along each branch; bracts herbaceous, lanceolate, glandular-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. |
sharply curved just below capsule, 2–10(–15) mm, shorter than to 2 times as long as capsule, with dense, patent, glandular pubescence. |
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, 3–5 mm, apex acute, glandular-hispid, hairs not extending beyond sepal tips, inner sepals with broad margins, outer sepals with very narrow margins; petals oblanceolate, 2–3 mm, shorter than sepals, apex 2-fid ca. 1/4 of length; stamens 5; styles 5. |
Capsules | cylindric, straight, 5–12 mm, 1.5–2 times as long as sepals; teeth 10, becoming outwardly coiled. |
narrowly cylindric, curved, 7–8.5 mm, ca. 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. |
light brown, 0.4–0.7 mm diam., tuberculate; testa not inflated. |
2n | = 36. |
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Cerastium texanum |
Cerastium axillare |
|
Phenology | Flowering spring. | Flowering summer. |
Habitat | Canyons, sandy washes, oak woodlands, mountain pine forests | Rocky canyons, woodland and mountain slopes |
Elevation | 1200-2800 m (3900-9200 ft) | 1300-2800 m (4300-9200 ft) |
Distribution |
AZ; NM; Mexico
|
NM; TX; Mexico |
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 axillare is similar to C. brachypodum in its short pedicels, but it is more viscid-pubescent, with a much more diffuse habit and solitary flowers widely spaced along the elongate, racemelike primary branches of the inflorescence. In addition, the leaves are usually acute, whereas in C. brachypodum they are usually obtuse. Cerastium axillare is confined in the United States to the trans-Pecos mountains of Texas and New Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 90. | FNA vol. 5, p. 81. |
Parent taxa | Caryophyllaceae > subfam. Alsinoideae > Cerastium | Caryophyllaceae > subfam. Alsinoideae > Cerastium |
Sibling taxa | ||
Synonyms | C. longepedunculatum var. sordidum, C. sordidum, Stellaria montana | |
Name authority | Britton: Bull. Torrey Bot. Club 15: 97. (1888) | Correll: Brittonia 18: 308. (1967) |
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