194 ANGIOSPERMAEDICOTYLEDONES 



Nectar is secreted by a fleshy disk below the ovary, stored in the corolla-tube 

 (2-3 mm. long), and protected from the entrance of rain-drops by a ring of white 

 hairs. Many insect visitors are attracted by the long conspicuous inflorescences with 

 their blue-violet flowers. Owing to protandry or protogyny, and the projection of 

 the stigma beyond the anthers in the mature stage, these visitors regularly effect 

 cross-pollination. 



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

 stated. 



Knuth, the honey-bee, 2 humble-bees, a Lepidopterid, and 3 hover-flies. Herm. 

 Mailer (Westphalia), 2 bees (Apis mellifica Z. 5. skg. and po-cltg., and Prosopis 

 communis Nyl. 5 and J, freq., skg.) and 3 fossorial wasps (i. Psammophila viatica 

 Z. J, skg. ; 2. Cerceris labiata F. j and S, freq., skg. ; 3. C. quinquefasciata Rossi, 

 skg.) : (Thuringia), a hawk-moth (Zygaena carniolica Scop., skg.) : (Alps), the 

 honey-bee, and the humble-bee Bombus alticola Krchb. 5, skg. Gerstacker (Bozen), 

 3 bees I. Xylocopa cyanescens Brull.] 2. X. valga Gers/.; 3. X. violacea Z. 

 (Ent. Nachr., Berlin, 1872, p. 272). Friese (Hungary), the bee Andrena braunsiana 

 Friese 5 freq., $ rare. Schletterer (Tyrol), 5 bees i. Andrena pectoralis Per., 

 very rare ; 2. Bombus argillaceus Scop. ; 3. B. variabilis Schmiedekn ; 4. Halictus 

 major Nyl. ; 5. Xylocopa valga Gersi. von Dalla Torre (Tyrol), 2 bees Halictus 

 major Nyl. 5, and Xylocopa violacea Z., } and J. Alfken (Bozen), the Scoliid Scolia 

 hirta Schr. 5 and J, not infreq., skg., and the bee Xylocopa violacea Z. }, po-cltg. 



2123. V. serpyllifolia L. (Herm. Muller, 'Fertilisation,' pp. 443-4; Kirchner, 

 'Flora V. Stuttgart,' p. 590; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) The 



whitish flowers of this species are traversed 

 by veins of a bluish colour. Though 



>^^^.^\^ usually homogamous, they are sometimes 



protogynous, or, according to Warnstorf, 

 protandrous. The stamens are tolerably 



^s^^^ close together above, and on either side 



the stigma, towards which the dehiscing 



Fig. 299. Vtronica serpyllifolia, L. (after ., r . < 



Herm. Miiller). (i) Flower seen from the front. SldCS Of the antherS are tUmcd, SOmctimeS 



?iSr^*^' *'"**'""': ^'P^**-. effecting automatic self-pollination. Warn- 

 storf, however, asserts that the stameni 

 project beyond the style, and turn downwards in the open flower during dehiscence 

 so that autogamy is rendered very difficult or entirely excluded. Owing to the clos* 

 proximity of the stigma and anthers, insect visitors can effect self- as well as cross 

 pollination. 



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

 stated. 



Herm. Miiller (on flowers kept in a room), the Muscid Calliphora erythrocephal 

 Mg.y skg. ; Scott-Elliot (Dumfriesshire), a Muscid (' Flora of Dumfriesshire,' p. 1 28). 



2124. V. aphylla L. (Herm. Miiller, 'Alpenblumen,' pp. 270-1 ; Schul; 

 'Beitrage,' II, pp. 11 7-1 8.) The flowers of this species agree with those < 

 V. Chamaedrys in colour, nectar-guides, and the form of the stamens. They ai 

 feebly protogynous. Although the bases of the filaments are attenuated, insect 

 which pay visits in sunny weather, touch the anthers and stigma indiscriminate! 

 effecting either cross- or self-pollination. The latter inevitably takes place in di 



@i 



ii 



