306 



BRITISH FLOWERING PLANTS 



Fio. 197 



mgrum. 



We have six species. V. Thapsus may be recognised 

 at once hj its decurrent leaves ; two are nearly glabrous 

 or slightly glandular-hairy — V. Blattaria, with pedicels 

 mostly longer, V. virgatum shorter, than the calyx. 



Of the other three, V. nigrum 

 has the leaves cordate, the others 

 narrow at the base ; of these, V. 

 Lychnitis has white flowers ; V. 

 pulverulentum, yellow. 



Crosses are not infrequent in 

 this genus. Gaertner found that 

 taking the produce of V. Lych- 

 nitis with pollen of its own 

 species as 100 seeds, when ferti- 

 lised with pollen from V. phoeni- 

 ceum it produced 90 seeds, with 

 that of V. nigrum 63, of V. Blat- 

 taria 62. On the other hand, 

 the ovary is quite sterile to 

 pollen of the same flower.^ 

 Kerner calls attention to the beautiful manner in 

 which the rain is collected and carried down to the 

 roots. The upper part of the leaves hangs downwards, 

 and consequently the rain drops off at the tip. But as 

 the leaves are shorter the higher their position on the 

 stem, the drops fall on that part of a lower leaf which 

 shelves towards the stem. Thus all the rain-water 

 received by the plant is eventually conducted to the 

 tap-root. 



V. Thapsus. — Two of the stamens are longer than the 

 other three, which have hairy filaments. The leaves 

 have stomata on both sides, and a hairy covering which 

 it is impossible to wet. The whole plant is tomentose. 

 V. Blattaria. — The flowers are homogamous, gener- 

 ally yellow, but sometimes white. According to Kerner 

 the corolla secretes nectar, but this is denied by 

 Kirchner. The pistil projects beyond the anthers. 

 Eventually the corolla drops ofi" and slips down the 



^ Darwin, Forms of Flowers. 



