54 
CERASTIUM 
Ephemeral ; closely allied to C. semidecandrum. Shoot with glandular hairs, branched at the 
base (except in the dwarf forms), lateral branches ascending or procumbent, rather dark green, often 
more or less purplish, 2 — 15 cm. long. Leaves forming a compact tuft which lasts into the 
flowering stage, spathulate to elliptical. Inflorescence rather lax, with about 3 — 15 flowers. Bracts — 
lowest pair wholly green, upper ones with a narrow scarious to subscarious margin. Pedicels about 
as long as the calyx, persistently curved at the top, reflexed from the base after flowering, 
ultimately erect except at the top. Flowers pentamerous, comparatively conspicuous, about 
3 — 6mm. in diameter; April to mid-May, the whole plant dead by mid-June or late-June. 
Sepals narrowly ovate, with a white scarious margin above. Petals about as long as the sepals, 
limb narrowly obovate, claw very short or absent, not contiguous, lobes nearly parallel, thicker 
and rather more deeply notched than in C. semidecandrum , of equal thickness throughout. Stamens 5. 
Capsule 1 '2 to 1*5 times as long as the calyx, slightly curved. Seeds small (o - 5 — o - 6 mm.), dark 
brown, with minute and acute papillae. 
Open, dry, sunny, and often bare situations on calcareous grassland, calcareous grassy banks, 
floors of limestone or chalk quarries and on the quarry -debris, and on calcareous cliffs ; local, from 
Devonshire and Kent northwards to Gloucestershire and Oxfordshire and with an outlying station 
in Suffolk ; ascending to 230 m. 
Europe, and perhaps elsewhere; but foreign distribution doubtful as British and continental 
botanists are not agreed as to the limits of the species. 
8. CERASTIUM SEMIDECANDRUM. Plate 51 
Alsine hirsuta minor C. Bauhin Pinax 251 (1671); Johnson Iter Cant. 3 (1629); C. hirsutum minus parvo 
flore Ray Syn. ed. 3, 348, t. 15, fig. 1 (1724)! 
Cerastium semidecandrum L. Sp. PI. 438 (1753); Smith FI. Brit. 497 (1800)!; Grenier Monogr. 
Cerast. 28 (1841); Schultz in Arch. FI. 24 (1842); Syme Eng. Bot. ii, 81 (1864); Rouy et Foucaud Ft. France 
iii, 219 (1896). 
Annual. Shoot usually pale green, with glandular hairs, branched at the base, lateral branches 
procumbent or ascending, about 2 — 20 cm. long, simple in the starved forms. Laminae subspathu- 
late to elliptical. Inflorescence rather lax. Bracts lowest pair herbaceous and smaller than the 
leaves, upper ones with broad white scarious margins. Pedicels 1*5 — 4'o times as long as the calyx 
in the fruiting state, reflexed after flowering, ultimately erect. Flowers usually pentamerous, 
5 — 7 mm. in diameter; mid-March to early July, the first species to come into flower. Sepals 5, 
very acute, with broad, white, scarious margins, with gland-tipped hairs on the back. Petals 5, 
about as long as the sepals or a little shorter, not contiguous, narrow, apical notch small and rather 
shallow. Stamens usually 5, antisepalous. Stigmas 5, antipetalous. Capsule about i - 2 — 2 - o times 
as long as the calyx, slightly curved. Seeds small (0*4 — o‘5 mm. long), pale brown, punctulate. 
(a) C. semidecandrum var. friesianum Babington in Mag. Zool. Bot. ii, 199 (1838); C. semidecandrum 
var. genuinum Rouy et Foucaud FI. France iii, 219 (1896). 
leones: — Smith Eng. Bot. t. 1630; Curtis FI. Lond. i, 93; FI. Dan. t. 1212; Reichenbach Icon, v, t. 228, 
fig. 4968. 
Camb. Brit. FI. iii. Plate 51. (a, b) Whole plants. ( c ) Bracts (enlarged). ( d ) Sepals (enlarged). 
( e ) Flowers. (/) Flower (enlarged), (g) Ovary, (h) Capsule and persistent calyx (enlarged). Huntingdon- 
shire (E. W. H.). 
Exsiccata : — Billot, 12, as C. semidecandrum ; Dickson, viii, 11, as C. semidecandrum ; Don, 59, as C. semi- 
decandrum ; Ehrhart herb. 95, as C. semidecandrum ; Fries, i, 39, as C. semidecandrum var. viscosum ; Reichenbach 
387 (a broad-leaved form), as C. semidecandrum ; Schultz {FI. Gall, et Germ.), 1 5 bis, as C. semidecandrum 
{H. N.), xvi, 1536; Thielens et Devos, iv, 306, as C. semidecandrum ; Wirtgen, xiii, 736, as C. semidecandrum 
forma procumbens ; Pel. Mail l. 936, as C. semidecandrum. 
Shoot not very strongly hairy or glandular-hairy, especially below. Pedicels of the lowest flower 
1 — 2 times longer than the calyx. 
This is the common form of the species. 
(b) C. semidecandrum var. glandulosum Koch Syn. 121 (1837) excl. syn. Fries 1 ; ed. 2, 133 (1845); 
C. varians var. pcllucidum Cosson et Germain FI. Env. Paris 38, Atlas, t. 5, fig. 7 — 9 2 (1845) excl. syn. Smith; 
C. semidecandrum var. pellucidum Rouy et Foucaud FI. France iii, 220 (1896). 
1 In the second edition of his Synopsis, Koch omitted the synonym C. glutinosum Fries to which he gave specific rank. 
2 This represents a plant intermediate between var. priesianum and var. glandulosum. 
