192 



ANGIOSPERMAE—DICOTYLEDONES 



2120. V. spuria L. (Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 326.) — The 

 flowers of this and the most nearly related species (V. longifolia L., and V. spicata L.) 

 are arranged in crowded spikes, and at the beginning of anthesis are adapted by 

 protogyny for cross-pollination. After a few days the stamens of the oldest (i.e. 

 lowest) flowers have elongated so much that their dehiscing anthers occupy the 

 position at first taken up by the stigma. Shortly before dehiscence, however, the 

 style has bent downwards in a knee-like fashion so that automatic self-pollination 

 cannot take place. Later on, when the pollen has been removed by insects or fallen 

 from the shrivelled anthers, the style straightens itself again, and projects almost 

 horizontally from the flower. Since the younger flowers pass through the same 

 stages of anthesis, though of course rather later, pollen can fall from their withering 



anthers upon the still receptive stigmas 

 of the lower flowers, in which the styles 

 have become horizontal. Geitonogamy 

 is thus effected. 



2121. V. longifolia L. ( = V. 



maritima L.). (Knuih, ' Bloemenbiol. 

 Bijdragen.') — Kerner says that geitono- 

 gamy takes place in this species as in 

 V. spuria. In garden plants I found the 

 flowers to possess the same mechanism 

 as the next species (V. spicata), except 

 that they are homogamous. At first 

 the two stamens diverge slightly out of 

 the flower for a distance of 5 mm., and 

 the dehisced surfaces of the anthers are 

 turned downwards. The style is still 

 short and bent downwards in a knee- 

 like way, so that the receptive stigma is 

 out of the line of fall of the pollen. 

 As the anthers shrivel the style elongates 

 and straightens itself, bringing the stigma 

 into pretty much the same position as the anthers at first occupied. 



Bee visitors, as they suck the nectar, settle on the lower part of the dense, 

 elongated, conspicuous inflorescence, and work upwards. They thus cross the lower 

 (older) flowers with pollen brought from other stocks, and dust themselves anew in 

 the upper (younger) flowers. Hover-flies when visiting fly from one blossom to 

 another, and most'y effect crossing, but also bring about self-pollination, for, in spite 

 of the deep and concealed position of the stigmas in pollen-containing flowers, these 

 are touched occasionally. Various parts of the visitors' bodies come into contact 

 with anthers and stigma, but they do not draw the stamens under their abdomen, for 

 the filaments are not thin at their bases. Muscids chiefly effect crossing, more rarely 

 autogamy, in an irregular way. The latter cannot take place automatically. 



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

 stated.— 



Fig. 297. Veronica JriUiculosa, L. (after Herm. 

 Mullen. A. Flower seen almost directly from the front 

 (X 4). B. Pistil and nectary («) from the side (x 7). 

 C Entrance of the flower showing the nectar-cover {sd) 

 and the roots of the filaments {Ji) ( X 7). 



