i86 



ANGIOSPERMAE—DICOTYLEDONES 



664. Veronica L. 



Flowers blue in colour, more rarely red or white ; with concealed nectar 

 secreted by a disk below the ovary, and stored in the lower part of the short 

 corolla-tube. The larger blossoms are usually homogamous or dichogamous 

 hover-fly flowers, the stamens and style serving as an alighting-platform. Kerner 

 says that geitogamy takes place in species with a spicate inflorescence. 



2111. V. Chamaedrys L. (Sprengel, 'Entd. Geh.,' p. 51; Herm. Miiller, 

 'Fertilisation,' pp. 438-9, ' Alpenblumen,' p. 272, 'Wait. Beob.,' Ill, p. 31; 

 Kirchner, 'Flora v. Stuttgart,' pp. 586-7; Loew, ' Bliitenbiol. Floristik,' p. 391; 

 Knuth, 'Bl. u. Insekt. a. d. nordfr. Ins.,' pp. iii, 164, ' Bloemenbiol. Bijdragen.') — 

 This species bears homogamous hover-fly flowers, arranged in tolerably conspicuous 

 racemes. The corolla is bright blue, decorated with darker lines and a lighter 

 centre. Nectar is secreted by a fleshy yellow hypogynous disk, and covered by 

 hairs lining the corolla-tube, these serving as a protection against rain. The style is 



Fig. 293. Veronica Chamaedrys, Z-. (^A after Herm. Miiller ; B, C, D from nature). A. Flower 

 seen from the front. B. Do., with the stamens drawn together, as done by a hover-fly. C. Do., with 

 a visitor (Ascia podagrica), which has drawn the stamens under its abdomen. D. Pistil and nectary 

 (X3). 



directed obliquely downwards, and the two stamens diverge laterally, automatic 

 self-pollination being therefore impossible, although stigma and anthers mature 

 simultaneously. The lower corolla-lobe is the most convenient alighting-platform, 

 so that when an insect settles it must first touch the stigma with its ventral surface. 

 The visitor then seizes the thin bases of the filaments, which are easily drawn 

 together, and its under-side is thus dusted afresh with pollen. In further visits the 

 same procedure is repeated, so that crossing is effected and fresh pollen taken up 

 each time. Even if a hover-fly settles on one of the lateral corolla-lobes the 

 under-side of its abdomen will sometimes be struck by one of the stamens. Kerner 

 finds that automatic self-pollination takes place in the closed flowers during bad 

 weather. He says that the flowers open about 9-10 a.m., closing again about 

 5-6 p.m. 



Visitors. — Alfken observed the following at Bremen and Hanover. — 



A. Coleoptera. Byrrhidae : i. Cistela sericea Forst. B. Diptera. {a) Em- 



pidae : 2. Empis tessellata F., skg. (1^) Syrphidae : 3. Ascia podagrica F., very 

 common, skg. ; 4. Syrphus balteatus Deg., skg. C. Hymenoptera. (a) Apidae : 

 5. Andrena chrysopyga Schenck S, occasional 6. A. cingulata F. 5 skg. and po-cltg.. 



