64 ANGIOSPERMAE—DICOTYLEDONES 



1807. -A. bryoides DC. ( = A. helvetica All.); 1808. A. imbricata Lam.; 

 and 1809. A. alpina Lam. ( = A. pubescens DC). (Herm. Muller, loc. cit.) — 

 These species are homogamous, and self-pollination takes place should insect-visits fail. 



1810. A. lactea L. (Briquet, ' Etudes de biol. flor. dans les Alpes Occident.') — 

 Briquet states that the flowers of this species are white with a yellow throat. The 

 limb of the corolla is 11-12 mm. in diameter, while the corolla-tube is 2 mm. broad 

 with an entrance of \ mm. As the flowers are homogamous, and the five anthers 

 almost touch the capitate stigma and project beyond it, automatic self-pollination 

 regularly takes place, and this is also effected by Diptera and small Lepidoptera. 

 Briquet was unable to confirm the statement of Kerner that nectar is secreted on the 

 upper surface of the ovary. Kirchner, however, found little drops of nectar on the 

 flat upper side of the ovary, both in this species and also in A. villosa, while Kerner 

 made similar observations for the species of Androsace in general. The flowers of 

 A. lactea possess an agreeable odour. 



1811. A. villosa L. (Briquet, op. cit.) — Briquet says that the flowers of this 

 species agree with those of A. lactea, except that the corolla is somewhat larger, and 

 its throat at first flesh-coloured and afterwards white. He observed no visitors. 

 In flowers examined by Kirchner the diameter was only 8-9 mm., and the throat of 

 the corolla golden-yellow at the beginning of anthesis, afterwards changing to a peach- 

 blossom red. MacLeod (' Pyreneenbl.,' p. 372) describes the flowers as white or 

 rose in colour, with purple or yellowish nectar-guides, and a somewhat ventricose 

 corolla-tube 3-3^ mm. long and constricted at the throat. 



Visitors. — MacLeod observed 3 flies and a Lepidopterid. 



1812. A. Vitaliana Lap. ( = Douglasia Vitaliana). — Treviranus describes this 

 species as dimorphous (Bot. Ztg., Leipzig, xxi, 1863, p. 6). 



543. Primula L. 



Literature. — Charles Darwin, J. Linn. Soc. Bot., London, vi, 1862, pp. 77-96 ; 

 Treviranus, Bot. Ztg., Leipzig, xxi, 1863; Hildebrand, op. cit., xxii, 1864; Scott, J. 

 Linn. Soc. Bot., London, viii, 1865; Pax, ' Primulaceae,' in Engler and Prantl, ' D. 

 nat. Pflanzenfam.,' IV, i. 



Flowers mostly homogamous and helerostylous-dimorphous, sometimes homo- 

 stylous; rarely protandrous and belonging to classes L or Hh (or Hb) ; sometimes 

 belonging to both Hh and L. Nectar is secreted by the base of the ovary, and sheltered 

 in the corolla-tube. The pollen-grains of the long stamens are larger than those of 

 the short ones, and the sligmatic papillae of the long styles are longer than those 

 of the short styles. 



Darwin's researches showed that ' legitimate ' pollination, in which the stigma of 

 the long (or short) style receives pollen produced at the same level by the anthers 

 of the long (or short) stamens, results in a much higher degree of fertility than 

 'illegitimate' pollination. {C/. Vol. I, pp. 47-8-) 



He also found Primula officinalis, P. sinensis, and P. Auricula very infertile 

 when insect-visits were prevented, but completely fertile when such visits were 

 permitted or artificial pollination effected. Legitimate unions were about li times 

 as fertile as illegitimate ones. 



