io6 



ANGIOSPERMAEDICOTYLEDONES 



Blomn. o. Befrukt.'; Warming, ' Arkt. Vaxt. Biol.,' p. 12 ; Kerner, 'Nat. Hist. PI.,' 

 Eng. Ed. I, II, pp. 366, 391 ; Warnstorf, Verb. bot. Ver., Berlin, xxxvii, 1896.) 

 This species bears humble-bee Lepidopterid flowers. Hermann Miiller (canton 

 Graubiinden), Lindman (Norway), and Warming (Iceland) describe it as feebly 

 protogynous, afterwards becoming homogamous, while Schulz (Westphalia and 

 Thuringia) observed it to be strongly protandrous. In all cases automatic self- 

 pollination is possible in the later part of anthesis. Kerner says that this autogamy 

 is brought about by gradual elongation of the corolla, so that the anthers of the 

 epipetalous stamens are brought into contact with the stigma ; and that during 

 unfavourable weather it may take place pseudo-cleistogamously in the closed flowers. 

 The flowers of plants from higher stations in Norway are of relatively large size, 

 and the stigma is not above the anthers but at the same level or even lower, so that 

 self-pollination is facilitated. It is otherwise in flowers from the Alps, for here the 



stigma at first projects 

 beyond the anthers, and 

 it is only in late anthesis 

 that the stylar branches 

 bend back far enough, 

 according to Hermann 

 Miiller, to effect autogamy. 

 Schulz, on the other hand, 

 says that this takes place 

 very infrequently. 

 ^^ m^HUi Mjj^^SB I Warnstorf describes 



^B ^-fl^Hr ^Flvli 11 the pollen-grains as yellow- 



^^B^H^^^ ^Hv il^Lli il^ ^^^ ^^ colour, ellipsoidal, 



^^0^H^^^ ^Iw llllwl (1^ traversed by several longi- 



^V J^V -^ In > Hw iflM tu^i"^^ furrows, densely 



^ "^y ^'^ (^ Yi papillose, on the average 



63 ;i long and 37.5 /* 

 broad. 



Visitors. The fol- 

 lowing were recorded by 

 the observers stated. 

 Lindman, humble-bees. Herm. Miiller, humble-bees and Lepidoptera, and also 

 perforations made by Bombus mastrucatus Gerst. Schulz (Central Germany), humble- 

 bees and Lepidoptera, and flowers perforated by the former. 



1915. G. Amarella L. (Herm. Miiller, 'Fertilisation,' p. 404; Warming, 

 * Arkt. Vaxt. Biol.,' p. 12; Schulz, ' Beitrage.') This species bears homogamous ^ 

 humble-bee flowers. The corolla-tube is 16-18 mm. long with an entrance 6 mm. 

 wide, into which a humble-bee can easily thrust its head, so that a proboscis 10-12 mm. \ 

 in length suffices to reach the nectar. This is secreted in the base of the flower by* 

 five fleshy green spots alternating with the filaments. There are long inwardly] 

 directed hairs at the junction between the tube and limb of the corolla, serving as] 

 a protection against unbidden guests (flies), and the nectar is sheltered from rain by] 

 closure of the corolla in dull weather. 



Fig. 265. Gentiana catnpestris, L. (from Herm. Mailer's ' Alpen- 

 blumen '). A. Flower partly dissected from the side. B, C, F. Relations 

 of stigmas and anthers at different stages. B. Stamen with dehiscing 



anther. D. Old pistil. E. Flower seen directly from above, a, anthers 

 7?, filaments ; , nectaries ; ov, ovary ; si, stigma. 



