48 
CERASTIUM 
(/ 3 ) forma nigrescens Druce in Moss Cambr. Brit. FI. iii, 48 ; C. latifolium Edmondston in Phytologist i, 
497 (1843) non al. ; C. latifolium var. edmondstoni 1 [Watson in Lond. Cat. Brit. PI. 2 (1844) nomen;] Edmondston 
FI. Shetl. 29 (1845); Babington Man. ed. 3, 54 (1851); N. E. Brown in Eng. Bot. ed. 3, suppl., 41 (1891); 
C. latifolium var. glaciale Babington Man. ed. 2, 56 (1847) non Gaudin ; C. latifolium var. nigrescens [Edmondston 
ex Watson Lond. Cat. Brit. PI. ed. 3, 3 (1850) nomen; Watson Cyb. Brit. 233 (1847) nomen;] Syme Eng. Bot. 
ii, 87 (1864); C. alpinum var. edmondstoni Hooker fil. Stud. FI. ed. 3, 60 (1884); C. arcticum var. edmondstoni 
Beeby in Scott. Nat. 7, 24 (1887)! 
Exsiccata ; — Herb. Druce, 897. 
Differs from the ordinary Alpine form in the following characters ; — Shoot more tufted and 
more purplish. Laminae broader. 
This local forma was first found by Thomas Edmondston, Junior, on Serpentine gravel near sea-level at Balta Sound, 
Unst, Zetland. It was described by him in 1845 f oc - Ft.) under the name of C. latifolium L. That it differed specifically 
from the plant which was at that time known by this name among British botanists was maintained by Edmondston but 
controverted by Watson (in Phyt. i, 586). 
“In 1897 and 1898 I brought home seeds and roots [of this Jorma from Zetland], and have the plants growing. ..in a 
mixture of Surrey soils. These plants have entirely lost their original colour, and have become completely green ; so that it 
appears that the only character is merely temporary and due to habitat. The Serpentine gravels of Unst contain a 
number of minerals, notably chromate of iron, and the colour of the leaves may, probably, be due to the influence of one 
of them. The Cerastium is by no means the only plant growing on these hills which is affected in this way ” (Beeby in Bot. 
Exch. Club. Brit, i, 568 (1899)). Watson, however, states that “the differences remain quite as strong in the plants raised 
from seeds near London {Cyb. Brit. 233 (1847)). 
Local ; damp Alpine grassland, rock-ledges, and talus, where the mineral content is high ; 
Carnarvonshire (fide Lange), and central and northern Scotland, and (as forma nigrescens ) Zetland ; 
ascending to 1200 m.; not known in England or Ireland. 
Faeroes, Iceland, Scandinavia, Spitzbergen ; Greenland. Unknown in central Europe. 
C. alpinum x arcticum (p. 46). 
C. arcticum x vulgatum Druce in Moss Cambr. Brit. FI. iii, 48 ; C. nigrescens x vulgatum Druce in 
Bot. Exch. Club Brit. Rep. for 1910 , ii, 498 (1911); x C. richardsoni 2 Druce loc. cit. 
Laminae narrow, acute, less pubescent than C. arcticum. Flowers intermediate in size between 
the putative parents. 
Carnarvonshire (Clogwyn, Snowdon). Not known elsewhere. 
4. CERASTIUM VULGATUM. Mouse-ear Chickweed. Plates 47; 45 
Alsine hirsuta myosotis Johnson Merc. Bot. 18 (1634); Ray Syn. ed. 3, 349 (1724). 
Cerastium vulgatum L. FI. Suec. ed. 2, 158 (1755); Syst. Nat. ed. 10, 1039 0759 ); Sp. PI. ed. 2, 
627 (1762); non herb.; Hudson FI. Angl. 175 (1762); Fries FI. Suec. 52 (1817) excl. syn. L. ; C. viscosum 
Linn, herb.!; Smith FI. Brit. 497 (1800); Eng. FI. ii, 330 (1824); non L. Sp. Pl:\ C. vulgare Hartman Skand. 
FI. 182 (1820); C. triviale Link Enum. Hort. Berol. i, 433 (1821) inch C. vulgatum et C. holosteoides ; Syme 
Eng. Bot. ii, 83 (1864); Rouy et Foucaud FI. France iii, 206 (1896); C. caespitosum Gurke Plant. Eur. ii, 222 
(1899) non Gilibert, nec Kitaibel (= C. arvense'), nec Triana et Planchon, nec Malmgren (= C. alpinum ). 
Perennial. Shoot hairy, barren branches about 4 — 12 cm. long. Leaves sessile. Laminae oblong 
or elliptical or narrowly spathulate, spreading, obtuse or rather acute. Inflorescence lax at maturity, 
with several flowers. Bracts herbaceous. Pedicel of the lowest flower about 1*5 cm. long, much 
longer than the bracts or calyx, reflexed after flowering, 2 — 4 times as long as the calyx when mature. 
Flowers pentamerous, very variable in size, from about 0'8 to 1 *5 cm. (or even rather more) in 
diameter ; April to October. Sepals with scarious margins, rather acute, hairy. Petals varying 
from a little longer than the sepals to twice as long, divided about half-way. Stamens 5 + 5. 
Capsule curved, cylindrical, up to twice as long as the calyx. Seeds reddish, tuberculate. 
Grenier {op. cit., p. 39) has a var. annuum of this species ; and Syme {op. cit. ii, p. 84) has a var. pentandrum which 
he declares is annual. Grenier’s variety is not taken up in any continental flora I have consulted. Syme has no specimen 
of his var. pentandrum in his herbarium ; and it is not known by tradition among the British botanists of to-day. Dr Moss 
informs me that he is frankly sceptical as to the existence of an annual variety of C. vulgatum , and suspects some confusion 
with one of the following species. 
The following varieties are arranged to show the transition from C. alpinum to the common lowland forms of C. vulgatum , 
and thus on to the annual forms. On the continent of Europe, there are analogous intermediate forms connecting C. alpinum 
and C. arvense. The indigenous C. arcticum connects C. alpinum with C. latifolium. Thus a great aggregate of forms exists, 
circling round C. alpinum , which renders the genus very difficult to classify, and tends to make the arrangement of the 
species a matter of individual predilection. 
1 After Thomas Edmondston (1825 — 1846), of Buness, Zetland. 
2 After Richard Richardson (1663 — 1741), of North Bierly, Yorkshire. 
