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A TEXTBOOK OF THEORETICAL BOTANY 



in January. Each day, during the cooler hours of the morning and again 

 in the evening, Humming Birds gathered in scores around the trees. He 

 noted that unhke insect visitors the birds dart from flower to flower in no 

 methodical manner. The movement of the wings is amazingly rapid, so 

 rapid as to be imperceptible to the human eye, yet in this way the birds can 

 hover almost stationary in front of a flower for sufficient time to gather the 

 nectar and in doing so to become dusted with pollen. The corolla of the 

 Bignonia flower (Fig. 1227) is very long and tubular, being composed of five 

 fused petals which diverge at the tip to form a two-lipped expanse. There 

 are four stamens together with one staminode, inserted on the corolla 

 tube with the anthers opening inwards, towards the centre of the flower. 

 The ovary is superior and bilocular and is prolonged into a very long slender 

 style with a pointed, apical stigma. In the young state the stamens move 

 towards the centre of the flower so that they more or less block the entrance. 

 During this stage, the style, which is not yet mature, lies against the lower 

 side of the corolla tube. Later, after the anthers have discarded their pollen, 

 they move back against the wall of the corolla, while the style occupies the 

 centre of the floral tube. Nectar is secreted at the base of the corolla tube 

 and, owing to the great length of the tube, can only be reached by the long 

 beaks and tongues of the Humming Birds. Even they must thrust their 

 heads deep into the flower to reach the nectar and in so doing the feathers 



Fig. 1228. — Strelitzia reginae. A, Flower emerging from spathe. 5 = sepals, i? = stigma, 

 pp = two united petals covering the stamens and style, po = domed petal over nectar. 

 B, View of pp and po from above. C, Section of pp towards apex. D, Section of pp 

 and po near base. (After Scott Elliott.) 



