652 CERASTIUM.~1 " [class X. ORDER IV. 



tions. Bracteas ovate lanceolate, with a pale thin membranous mostly 

 jagged border; in (2. pumilum the lower ones are entirely herbaceous. 

 Flowers small, white. Peduncles longer than the calyx, sometimes 

 deflexed, but rarely so when in fruit. Cali/x of five, rarely four 

 segments, ovate lanceolate, downy, and mostly viscid, with a pale thin 

 membranous margin, mostly jagged at the apex. Petals about as long 

 as the calyx segments, and more or less deeply cloven. Stamens ten, 

 but frequently only five, and sometimes four, nearly as long as the 

 petals, anthers small, ovate, yellow. Str/les short, spreading, five, 

 sometimes four. Capsule cylindrical, membranous, longer than the 

 calyx, straight, or towards the apex curved upwards; it is not, how- 

 ever, uncommon to find it on the same plant both straight and curved, 

 and scarcely longer than the calyx, or nearly as long again. Seeds 

 numerous, small, pale brown, flattish, roundish, ovate, with a rough 

 margin. 



Habitat. — Old walls, dry sandy and waste places; not unfrequent. 



Annual ; flowering from March to J une. 



This is an extremely variable species, respecting which the English 

 Botanist has been much confused, on account of the descriptions and 

 figures given of the C. tetrandrum having been made from cultivated 

 specimens, a mistake which is so apt to lead to error, especially in such 

 plants as the present, which we observe to vary so greatly even in the 

 wild state, from a change in the situation of its growth from a poor dry 

 to a more luxuriant soil; and our own observations with respect to the 

 union of these two species confirm the opinions of Hooker, Greville, 

 Lindley, and others. The hairiness and viscidity of the whole plant 

 seems also to depend upon the situation of its growth, for, when grown 

 in a good moist soil, the hairiness, for the most part, disappears ; but 

 if in a dry sterile one not only is it more hairy, but the hairs, especially 

 in the upper part of the stem and branches, become tipped with small 

 globose fleshy glands, which secrete a viscid fluid. This admirable 

 adaptation to circumstances will not fail to excite in the mind of the 

 student his admiration, and more than interest him when he knows 

 that He who designed them madenothing without an object, and only 

 to answer some good end ; and as the hairiness and viscidity disappear 

 under one condition, we may conclude that under such circumstances 

 they are not needed in the economy of the plant, but on the other 

 hand when they are found in an opposite condition of the plant, the 

 same reasoning will bring us to the conclusion that they are requisite 

 for the purposes of the plant : and as in the one case where the plant 

 finds a supply of moisture in the soil in which it grows, and the hairs 

 and glands are not present, and in the other, where the soil is dry, 

 and the plant provided with these hairs and glands, the office which 

 they perform in the economy of the plant may be sought for in their 

 being a means of providing it with moisture. The changes here ob- 

 served to take place in this species also takes place in the others as 

 well as those of other genera. 



