48 BRITISH FLOWERING PLANTS chap. 



some slightly hairy, in others {R. arvensis, R. parvi- 

 jlorus) covered with tubercules or spines which are 

 often more or less hooked, and no doubt serve to pro- 

 mote the dispersion of the seeds. In some {R. scapi- 

 gerus, R. multiscapus, etc.) the style itself is hooked. 

 In other cases dispersion is aided by the presence of 

 wings, or (some species of Clematis) by a long feathery 

 process consisting of the persistent style. This prob- 

 ably serves another useful purpose by fixing the seed 

 to the damp soil, thus helping the seedling to escape 

 from the testa. 



Clematis 



The flowers are honeyless, and are visited by insects 

 for the sake of the pollen. They have white or coloured 

 sepals and no petals. The genus is widely spread over 

 the globe. 



Of this genus we have only one species, 0. Vitalba. 

 It has a woody stem, and climbs by means of the 

 stalks of the leaves, which are opposite, compound, 

 and without stipules. The flowers are sweet, greenish- 

 white, and small, but conspicuous from being collected 

 in clusters, whence Dodonseus gave it the name of 

 Vitalba — the White Vine. There are no petals ; the 

 sepals are four in number, the stamen and carpels 

 numerous. The persistent style of the one-seeded fruit 

 is produced into a long feathery awn, which, as in other 

 similar cases, assists in the dispersal by wind, and has 

 originated one of its English names — Old Man's Beard. 

 The other. Traveller's Joy, given it, I believe, by Gerard, 

 refers to its partiality for roadside and other hedges. 

 In other species of the genus the style is short and 

 beardless. 



Clematis is visited and fertilised by several species of 

 flies and bees which feed on the pollen. Most flowers 

 are visited by small insects for the sake of their pollen, 

 and I only mention such visits when they assist 

 in the fertilisation. It is slightly protogynous. It 

 prefers calcareous soils, and is very luxuriant on chalk. 



