152 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Petals shorter than or but slightly exceeding the sepals. 

 Inflorescence dense, the pedicels all or nearly all much shorter than the calyx. 

 Plants annual; leaves elliptic to broadly oval, obtuse or rounded at the apex; 

 petals shorter than the calyx; capsule about twice as long as the sepals. 



2. C. viscosum. 

 Inflorescence loose and open, at least in age, the pedicels longer than the calyx. 

 Pedicels several times as long as the calyx; capsule about 3 times as long as the 

 sepals; plants annual; leaves linear-oblong, acute or acuminate; petals 



slightly longer than the calyx 3. C. longipedunculatum. 



Pedicels twice as long as the calyx or shorter; capsule not more than twice as 

 long as the sepals; plants perennial; leaves oblong to oval, usually obtuse; 

 petals about equaling the calyx 4. C. vulgatum. 



1. Cerastium velutinum Raf. Chickweed. 

 Common in open rocky places along the Potomac. Apr.-May. Northern states, 



south to Va. ( C. ohlongifolium Torr. ) 



2. Cerastium viscosum L. Mouse-ear chickweed. 

 Common in wet meadows along the upper Potomac and occasional elsewhere. 



Apr.-May . Native of Eur. ; widely naturalized in N . Amer. 



3. Cerastium longipedunculatum Muhl. Nodding chickweed. 

 Moist groimd, chiefly along the upper Potomac. May. Widely distributed in N. 



Amer. (C. nutons E.af.) 



4. Cerastium vulgatum L. Mouse-ear chickweed. 

 Wet meadows and waste ground about Washington; Marlboro. Apr.-May. Native 



of Eur.; widely naturalized in the U. S. 



Cerastium semidecandrumL., an annual species with smaller leaves, was collected 

 once by 0. F. Wheeler in the Department of Agriculture grounds. A European spe- 

 cies, sparingly naturalized from Mass. to Va. 



4. ALSINE L. 



Stems and leaves glabrous; leaves 1.5-8 mm. wide. 

 Leaves linear or nearly so, not noticeably broadest at the base; seeds smooth. 



1. A. longifolia. 

 Leaves lanceolate or elliptic, usually broadest below the middle; seeds rough. 



2. A. graminea. 

 Stems and leaves more or less hairy; leaves 4rA0 mm. wide. 



Leaves all sessile or nearly so, obtuse or acutish; sepals sparsely hairy or glabrous; 



petals longer than the calyx; stamens 10 3. A. pubera. 



Leaves petioled, the lower petioles as long as the blades, the blades acute to long- 

 acuminate; sepals densely hairy; petals shorter than the calyx; stamens 3-7. 



4. A. media. 



1. Alsine longifolia (Muhl.) Britton. Stitchwort. 

 Frequent in damp meadows. Apr.-June. Widely distributed in N. Amer ; also in 



Eur. and Asia. (Stellaria longifolia Muhl.) 



2. Alsine graminea (L.) Britton. Starwort. 

 Department of Agriculture grounds and Ammendale. Native of Eur. and Asia; 



sparingly adventive in eastern N. Amer. (Stellaria graminea L.) 



3. Alsine pubera (Michx.) Britton. Star chickweed. 

 Shaded rocks and woods; common. Apr.-May. N. J. to Ind. and Ga. (Stellaria 



pubera Michx.) 



The plant sometimes flowers in late .autumn, specimens having been found in flower 

 as late as November 10. In late summer the plants send up long Adgorous shoots with 

 very large broad leaves. The flowers are shown in plate 31B. 



