38 



ANGIOSPERMAEDICOTYLEDONES 



to the early time of flowering, insect visitors^ are considerably fewer in number than 

 in the last species. 



Here again the stigmas are mature when the flower opens, and curve outwards 

 pretty strongly. The calyx which is at first 1-5 cm. in diameter exceeds them in 

 length by several millimetres, they in their turn being longer by about 5 mm. than the 

 as yet quite immature anthers, which project but little beyond the nectaries. 



An insect when sucking nectar is obliged to hold on by the downwardly-directed 

 styles, and if it has come from a flower in the second condition will dust the 

 stigmas with foreign pollen. The styles are therefore considerably stouter than 

 in the last species, and their curvature in correspondence with the wider opening 

 of the flower is greater. The tips of the styles are capitate. 



The stigmatic papillae are larger than in H. foetidus. They closely cover the 

 dilated end of the style, along the inner side of which they are continued for some 

 distance. The pollen-grains of the two species are of about the same size (0-04 mm. 

 long, and 0-02 mm. broad) and are of a similar elongated ovoid form. In H. viridis the 

 stigmatic papillae are somewhat conical, so that a pollen-grain exactly fits into the 

 space between two of them, and to a certain extent is held fast. 

 1, 



Fig. 13. Helleborus viridis, L. (From nature : the three front sepals have been removed.) i. Flower 

 in the first (female) condition. 2. Flower in the second (male) condition, k, sepal ; , nectary; a, imma- 

 ture anther ; a', mature anther ; s, stigma. 



As the stigmas gradually wither, the stamens elongate centripetally, turning 

 outwards the sides which are covered with pollen to the place that the stigmas 

 occupied in the first stage of flowering. At the same time the sepals spread out 

 so as to increase the diameter of the flower to 3 cm. 



The nectaries are considerably larger than in the last species, and the flower 

 being pendulous rain is kept away from their secretion. The blossom having 

 a much larger opening than in H. foetidus, insect visitors easily reach the nectar- 

 cups without much searching, and suck while holding on by the styles and stamens, 

 so that here again cross-pollination must ensue. None of the insect visitors I 

 observed were engaged solely in gathering pollen. 



Visitors. I observed the following in Kiel Garden. 



Hymenoptera. 1. Apis mellifica Z. ; 2. Bombus terrester Z. $; 3. B. lapi- 

 dorius Z. 



MacLeod noticed an Andrena in the Pyrenees, and Burkill ('Fertilisation of 

 Spring Flowers ') saw on the coast of Yorkshire, Bombus terrester Z., skg. 





