Cerastium texanum |
Caryophyllaceae subfam. alsinoideae |
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Chihuahuan mouse-ear chickweed, Texas chickweed, Texas mouse-ear chickweed |
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Habit | Plants annual, with slender taproot and branched caudex. | Herbs, winter annual, annual, biennial, or perennial; taprooted and/or rhizomatous, rarely with tuberous thickenings (Pseudostellaria). |
Stems | erect, sparingly branched proximally, slender, 15–35 cm, sparsely glandular-pilose; small axillary tufts of leaves absent. |
prostrate to ascending or erect, simple or branched. |
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. |
opposite, connate proximally or not, often petiolate (basal leaves), not stipulate; blade subulate or linear to spatulate, lanceolate, or broadly ovate, seldom succulent. |
Inflorescences | very open and loose, 2–9(–25)-flowered cymes; bracts narrowly lanceolate, pilose. |
terminal or axillary cymes, or flowers solitary; bracts foliaceous or reduced, herbaceous to scarious (or rarely absent); involucel bracteoles absent. |
Pedicels | straight, becoming sharply deflexed at base, slender, 5–20 mm, elongating in fruit, 1.5–4 times as long as sepals, glandular-pilose. |
present or rarely flowers sessile. |
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. |
bisexual or seldom unisexual, sometimes inconspicuous; perianth and androecium hypogynous or perigynous, often slightly; hypanthium cup-, dish-, or disc-shaped; sepals (4–)5, distinct or seldom connate basally, sometimes hooded, not awned; petals absent or (1–)4–5, usually white, sometimes translucent, yellowish white, pink, or brownish, seldom clawed, auricles absent, coronal appendages absent, blade apex entire or 2-fid, sometimes jagged or emarginate, rarely laciniate; stamens absent or (1–)5(–10), in 1 or 2 whorls, arising from base of ovary, a nectariferous disc, or sometimes the hypanthium or hypanthium rim; staminodes absent or 1–5(–8); ovary 1- or rarely 3-locular (Wilhelmsia); styles (2–)3–5(–6), distinct; stigmas (2–)3–5(–6). |
Fruits | capsules, or rarely utricles (Scleranthus), opening by (2–)3–6, occasionally 8 or 10 valves or (3 or) 6–10 teeth; carpophore present or often absent. |
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Capsules | cylindric, straight, 5–12 mm, 1.5–2 times as long as sepals; teeth 10, becoming outwardly coiled. |
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Seeds | red-brown, 0.4–0.7 mm diam., tuberculate; tubercles ± pointed; testa not inflated. |
1–60+, yellowish or tan to dark red or often brown or black, usually reniform or triangular to circular and laterally compressed or ovoid to globose, rarely oblong and dorsiventrally compressed (Holosteum); embryo usually peripheral and curved, rarely central and straight (Holosteum). |
x | = 6–15, 17–19, 23. |
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2n | = 36. |
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Cerastium texanum |
Caryophyllaceae subfam. alsinoideae |
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Phenology | Flowering spring. | |
Habitat | Canyons, sandy washes, oak woodlands, mountain pine forests | |
Elevation | 1200-2800 m (3900-9200 ft) | |
Distribution |
AZ; NM; Mexico
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North-temperate regions; South America (Andean region); Europe (Mediterranean region); w Asia; c Asia (Himalayas, Mediterranean region); Africa (Mediterranean region) |
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.) |
Genera 30, species ca. 1040 (16 genera, 137 species in the flora). Alsinoideae, often considered basal in the family and the least specialized, is in some ways the most heterogeneous of the subfamilies. Members of its largest tribe (Alsineae) share the following characteristics: stipules absent, sepals free or at most basally connate, and capsular fruits. Indehiscent fruits, relatively short hypanthia, and other floral reductions occur in varying combinations in the approximately 30 species placed in four other tribes. A broad molecular survey of Alsinoideae has revealed two major lineages and lack of support for the existing tribal circumscriptions (M. Nepokroeff et al. 2002). About three-fourths of the species are members of Arenaria, Cerastium, Minuartia, and Stellaria. Attempts have been made to move Scleranthus (fruit a utricle surrounded by an enlarged hypanthium) from Alsinoideae to either Paronychioideae (J. Hutchinson 1973, as Illecebraceae) or Scleranthaceae (A. Takhtajan 1997). Recent molecular and morphological studies by R. D. Smissen et. al. (2002, 2003) supported its retention in the Alsinoideae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 90. | FNA vol. 5, p. 50. |
Parent taxa | Caryophyllaceae > subfam. Alsinoideae > Cerastium | Caryophyllaceae |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | C. longepedunculatum var. sordidum, C. sordidum, Stellaria montana | |
Name authority | Britton: Bull. Torrey Bot. Club 15: 97. (1888) | Fenzl: in S. L. Endlicher, Gen. Pl. 13: 963. (1840) |
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