FLAX TRIBE 



47 



high. The ovate leaves are fringed and slightly stalked ; flowers 

 larger and with more conspicuous petals than in A. serpylli folia. 

 Rare, limestone district of Sligo, Ireland. Fl. July. Perennial. 



8. A. trinervis (Three-nerved Sandwort). Leaves egg-shaped, 

 acute, the lower ones stalked, 3-5 nerved, fringed : flowers solitary 

 from the forks of the stem and axils ; sepals 3-nerved, the central 

 nerve rough. A weak, straggling plant, about a foot long, ap- 

 proaching the chickweed (Stellaria media) in habit, from which, 

 however, it may at once be distinguished by its undivided petals. 

 Fl. May, June. Annual. 



13. Cerastium {Mouse-ear Chickweed) 



1. C. vulgatum (Mouse-ear Chickweed). A com- 

 mon annual weed, downy and generally viscid, 

 with straggling branched stems 1-2 feet long, and 

 inconspicuous flowers, of which the petals are 

 usually shorter than the calyx, or occasionally 

 wanting. The seed-vessels when ripening lengthen 

 beyond the calyx and become curved. An in- 

 definite number of very confusing varieties occur, 

 which it is unnecessary to describe here. Fl. all 

 the summer. 



2. C. arvense (Field Mouse-ear Chickweed). 

 An uncommon species, smaller than the fore- 

 going, less downy and viscid ; leaves narrower, and 

 with conspicuous white flowers, with petals twice 

 as long as the sepals. Fl. June, July. Perennial. 



3. C. Alpinum (Alpine Mouse-ear Chickweed). A short plant 

 with ascending stems ; leaves broader than in the foregoing, and 

 white with silky down ; flowers large and white. More or less 

 frequent in the Highlands of Scotland, and occasional in the north 

 of England. Fl. summer. Perennial. 



4. C. trigynum (Starwort Mouse-ear Chickweed). A rare form 

 found on the Breadalbane and other mountains in Scotland. Stems 

 slender, ascending, about 6 inches long, with a line of hairs on 

 alternate sides between each pair of leaves ; otherwise the plant is 

 usually glabrous ; leaves narrow ; teeth of the seed-vessel twice as 

 many as the styles ; styles usually 3, occasionally 4-6. Fl. July, 

 August. 



Cerastium 

 Vulgatum 

 (Mouse-ear Chick- 

 weed) 



Natural Order XV 



LINACE^E. The Flax Tribe 



Sepals 3-5, overlapping when in bud, persistent; petals equal in 

 number to the sepals, twisted when in bud, falling off very soon 



