24. Cerastium texanum Britton, Bull. Torrey Bot. Club. 15: 97. 1888.
Chihuahuan mouse-ear chickweed
Cerastium longepedunculatum Muhlenberg ex Britton var. sordidum (B. L. Robinson) Briquet; C. sordidum B. L. Robinson; Stellaria montana Rose
Plants annual, with slender taproot and branched caudex. Stems erect, sparingly branched proximally, slender, 15-35 cm, sparsely glandular-pilose; 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 ob-lanceolate, 7-30 mm, apex acute, pilose. Inflorescences very open and loose, 2-9(-25)-flowered cymes; bracts narrowly lanceolate, pilose. Pedicels straight, becoming sharply deflexed at base, slender, 5-20 mm, elongating in fruit, 1.5-4 times as long as sepals, glandular-pilose. 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. Capsules cylindric, straight, 5-12 mm, 1.5-2 times as long as sepals; teeth 10, becoming outwardly coiled. Seeds red-brown, 0.4-0.7 mm diam., tuberculate; tubercles ± pointed; testa not inflated. 2n = 36.
Flowering spring. Canyons, sandy washes, oak woodlands, mountain pine forests; 1200-2800 m; Ariz., N.Mex.; Mexico.
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.
Turner, B. L. 1995. Cerastium texanum does not occur in Texas. Phytologia 79: 356-363.