VACCINIA CEAE 



31 



irregularly tetrahedral or of indeterminate shape, tuberculate, up to 44 /u, in 

 diameter. 



Visitors. The following were recorded by the observers, and for the localities 

 stated. 



Knuth (Usedom, where the plant covers large tracts), Apis and 3 humble-bees 

 (i. Bombus hortorum Z. 5; 2. B. lapidarius Z. ^ ; 3. B. terrester Z. 5), all freq., skg. 

 A. Rose (Thuringia), two humble-bees Bombus hortorum Z., and B. terrester Z. 

 Alfken (Bremen), 4 humble-bees i. Bombus jonellus -A', 5 ; 2. B. muscorum 

 Jf". 5; 3. B. proteus Gersf. 5; 4. B. terrester Z. 5. Friese (Thuringia), the bee Osmia 

 nigriventris Zg//. Herm. Miiller (Alps), Apis and 3 humble-bees. Scott-Elliot 

 (Dumfriesshire), an Empid and a Muscid ('Flora of Dumfriesshire,' p. 11 1). 



The arctic variety pu- 

 milum Hornem. (Green- 

 land, Labrador) has been 

 investigated by Warming, 

 who describes it as follows 

 (Bot. Tids., Kjobenhavn, 

 1895, pp. 44-6). 



The flowers vary in 

 size, sometimes being only 

 half as large as those of 

 the type form, though re- 

 latively broader. In these 

 small flowers the style only 

 reaches to the mouth of 

 the corolla, where the 

 anthers are situated, so 

 that self-pollination can easily take place. But in the larger ones the style projects 

 from the corolla, as in the type form (Fig. 2 1 8). Fruits are only set in warm years. 



Ekstam describes the flowers as feebly protandrous, odourless, and 4-8 mm. in 

 diameter. 



1754. V. Oxycoccos L. (=Oxycoccos palustris Pers.). (Sprengel, 'Entd. Geh.,' 

 pp. 228-9; Herm. Miiller, 'Weit. Beob.,' Ill, pp. 67-9; Warming, ' Bestovnings- 

 maade'; Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 107; Warnstorf, Verb. bot. 

 Ver., Berlin, xxxviii, 1896.) Although Kerner gives an admirable account of the 

 flower mechanism of this species, he failed to observe that the visits of bees inevitably 

 effect crossing. The red wheel-shaped corolla is reflexed, and Sprengel says that the 

 anthesis of individual flowers lasts for eighteen days. 



As in other species, the nectar is sheltered from rain by the pendulous position of 

 the flower, and Kerner says it is protected against unbidden guests by the stamens, 

 which closely surround the style. Hermann Muller points out that the stamens are 

 also the means by which bees of suitable size are forced to eff'ect crossing. They are 

 so greatly broadened as to form a tube round the style, their outer surface is rough 

 with short hairs, and their closely apposed edges are beset with longer curly hairs, so 

 closely interwoven that a nectar-seeking insect is unable to succeed in penetrating 

 between them. The anthers are borne on the inner sides of the filaments, and each 



Fig. 218. yacciniuftt Viit'S'/daea, Z,. (sLher K-WaLTming). A-G. 

 Var. pumilum, from Greenland. A, B. Larger flowers. C, D. 



Smaller flowers. E, F. A stamen from A. G. Nectary. H. Type- 

 form, from Stockholm. (A-D, H x 4.) 



