Cerastium Cerastium, L.

22. C. arvense L. View in CoL , Sp. PI. 438 (1753).

Perennial 5-30 cm, loosely matted to caespitose, with procumbent leafy stems freely rooting at lower internodes. Leaves linear-acicular to ellipticlanceolate. Bracts ciliate, with scarious margins; petals 2, rarely up to 3, times as long as sepals. Seeds seldom more than 1 mm, tuberculate. Most o fEurope except the extreme north. Al Au Be Br Bu Cz *Da Ga Ge G r H b He Ho Hs Hu It Ju Po Rm Rs (B, C, W) *Su [Fe N o *Rs (N)].

The following grouping of subspecies is provisional and it seems possible that some of them may merit specific rank. Two different chromosome numbers have been recorded within the complex. Sufficient data on the correlation between cytological and morphological characteristics are, however lacking. 1 Lower leaves attenuate, shortly petiolate; seeds 1-1-1-7 mm

2 Sepals lanceolate, subacute (g) subsp. lerchenfeldianum

2 Sepals ovate-lanceolate, subobtuse (h) subsp. glandulosutn

1 Leaves sessile; seeds not more than 1 mm

3 Plants mostly loosely matted; non-flowering shoots nearly as long as flowering stems (f) subsp. arvense

3 Plants ±caespitose; non-flowering shoots much shorter than flowering stems

4Leaves subulate from a wide base, obtuse, imbricate (a) subsp. thomasii

4Leaves linear-acicular to lanceolate, acute, usually not imbricate

5 Seldom more than 10cm; capsule as long as or slightly longer than sepals (b) subsp. strictum

5 Usually 10-30 cm; capsule up to twice as long as sepals

6 Non-flowering axillary shoots long; leaves up to 40 mm, linear-filiform (d) subsp. suffruticosum

6 Non-flowering axillary shoots short; leaves seldom more than 20 mm, linear to lanceolate

7 Leaves linear-acicular, stiff (c) subsp. pallasii

7 At least the upper cauline leaves 2-4 mm wide, linearlanceolate to lanceolate (e) subsp. ciliatum