GENUS 2. 



CHICKWEED FAMILY. 



47 



2. CERASTIUM L. Sp. PI. 437. 1753. 



Annual or perennial, generally pubescent or hirsute herbs, with terminal dichotomous 

 cymes of white flowers. Sepals 5, rarely 4. Petals of the same number, emarginate or bifid 

 (rarely wanting). Stamens 10, rarely fewer. Styles equal in number to the sepals and 

 opposite them, or in some species fewer. Capsule cylindric, i-celled, many-ovuled, often 

 curved, dehiscent by 10, rarely 8, apical teeth. Seeds rough, more or less flattened, attached 

 by their edges. [Greek, horny, referring to the horn-like capsule of many species.] 



About 50 species, of wide geographic distribution, most abundant in the temperate zones. Type 

 species : Cerastium arvense L. 

 Petals equalling the sepals, or shorter ; annuals. 



Pedicels not longer than the sepals; flowers glomerate. i. C.viscosum. 



Pedicels at length longer than the sepals ; flowers cymose. 



Leaves 2"-^" long; capsule nearly straight. 2. C. semidecandrum. 



Leaves ^"-12" long; capsule curved upward. 3. C.vulgatum. 



Petals manifestly longer than the sepals (rarely wanting). 

 Annuals, viscid-pubescent ; flowers 2" -3" broad. 



Pedicels much longer than the calyx. 4. C. longipedunculatum. 



Pedicels shorter than or but little exceeding the calyx. 5. C. brachypodum. 



Perennials, glabrous or pubescent ; flowers 6"-io" broad. 

 Styles always 5. 



Leaves linear or lanceolate-oblong, mainly acute. 



Leaves linear to linear-lanceolate ; pod about half as long again as the calyx. 



6. C. arvense. 

 Leaves lanceolate to oblong-lanceolate ; pod twice as long as the calyx. 



. 7. C. velutinum. 



Leaves oblong-ovate, obtuse. 8. C. alpinum. 



Styles 3 (very rarely 4 or 5) ; leaves linear-oblong. 9- C.cerastioides. 



i. Cerastium viscosum L. Mouse-ear 

 Chickweed. Fig. 1763. 



Cerastium viscosum L. Sp. PI. 437. 1753. 

 Cerastium glomeratum Thuill. Fl. Paris, Ed. 2, 226. 

 1824. 



Annual, tufted, stems ascending or spreading, 

 densely viscid-pubescent, 4-12' long. Leaves 

 ovate or obovate, or the lower spatulate, 4"-i2" 

 long, 3"-7" wide, obtuse ; bracts small, herba- 

 ceous; flowers about 2"-$" broad, in glomerate 

 cymes, becoming paniculate in fruit; pedicels 

 snorter than or equalling the acute sepals; petals 

 shorter than the calyx, 2-cleft. 



In waste places and meadows, New Brunswick to 

 Ontario, Florida, Arkansas and Mexico. Naturalized 

 from Europe. Naturalized also in the West Indies, 

 Central America, and on the Pacific Coast. April-July. 



2. Cerastium semidecandrum L. Small or 



Five-stamened Mouse-ear Chickweed. 



Fig. 1764. 



Cerastium semidecandrum L. Sp. PI. 438. 1753. 

 Cerastium vulgatum var. semidecandrum A. Gray, Man. Ed. 

 5, 94. 1867. 



Low, tufted, erect or decumbent, annual, 2'-6' high, 

 finely viscid-pubescent. Leaves ovate, or the lower 

 spatulate, 2"-4" long, obtuse ; bracts scarious, mem- 

 branous ; inflorescence cymose; pedicels at length 

 longer than the calyx; flowers i"-ii" broad; sepals 

 lanceolate, acute, scarious-margined, slightly exceeding 

 the emarginate petals ; capsule narrow, nearly straight ; 

 stamens often 5. 



In dry, sterile soil, Massachusetts to Virginia. Natural- 

 ized from Europe. Called also spring mouse-ear. April- 

 May. 



