OROBANCHACE^ 



303 



The stem is covered with glandular hairs. The plant 

 is parasitic on Hemp, and is occasionally found in 

 Britain, but not native. 



Lathr^a 



Parasitic on the roots of trees. Protogynous humble 

 bee flowers. Nectar secreted by a gland on the under 

 side of the ovary. 



L. Squamaria(Toothwort). — Theplant is flesh-coloured 

 or slightly bluish, with red or purple streaks. The 

 flowering stems and the rhizome bear scales, those 

 underground thick and fleshy. The flowers are in a 

 one-sided spike, which is at 

 first bent and does not 

 become straight until the 

 uppermost flower is ready to 

 open. The stigma then pro- 

 jects beyond the flower-tube, 

 within which lie the still 

 unripe anthers, so that, as 

 the honey is abundant and 

 humble bees assiduously visit ^'^- ^^^■ 

 the flowers, cross-fertilisation ^'Voot'rf MhJa. '''x 2."'''''^°™'^ 



is effectively provided for. Fig.193.— Longitudinalsectiontlnougli 



For a short time after the ^ ^™^' 

 anthers open the stigma remains fresh, yellow, and 

 capable of impregnation. Soon, however, it dries and 

 shrivels up. The dry pollen falls from the anthers, but is 

 supported by a thick brush of hairs. If, however, the 

 short points of the anthers are pressed aside by the pro- 

 boscis of the bee the pollen drops out on to the insect's 

 head. In the meanwhile the corolla -tube lengthens 

 and eventually covers the stigma. The stamens also 

 elongate, and project at last beyond the tube ; the dry 

 pollen is carried away by the wind, and as the plants 

 generally grow in patches, some must occasionally 

 reach the stigmas of younger flowers. The underground 

 scales resemble those on the stem in outline. At 

 first sight they seem to be squarely mounted on a short 



Fig. 193. 



