236 



FLOWERS AND THEIR WORK. 



(e) Examine the flowers of a Violet and a Pansy (Figs. 84, 85). 

 Note the five free green sepals, each prolonged below its insertion ; 



the five free petals, of which 

 the two upper pairs are lop- 

 sided while the lowest petal is 

 symmetrical and bears a spur ; 

 the five stamens, almost stalk - 



,,SEPALS 



--SPUR 

 NECTARY 



-ANTHER 

 -SCALE 



CAVITY OF 



STYLE 



SCRAPER 



less, the anthers forming a ring 

 round the ovary and each 

 bearing a triangular orange- 

 coloured scale on top ; the two 

 nectaries, which grow from 

 the backs of the two lowest 

 stamens and project into the 

 spur; the one-chambered 

 ovary, containing numerous 

 ovules on three parietal pla- 

 centas ; the style, with its free 

 end thickened and produced 

 into a beak which projects 

 beyond the cone formed by 

 the anther-scales and hangs 

 over the entrance to the spur. 

 Sketch (1) the inner surfaces 

 of an upper petal, a side petal, 

 and the spurred front petal, 

 detached ; (2) the entrance to 

 the spur, showing the parts 

 above, below, and at each 

 side, in their natural posi- 

 tions ; (3) the spur cut open, displaying the nectaries ; (4) one of the 



three upper stamens; (5) one of the lower 



stamens ; (6) the pistil in side view ; (7) the 



ovary cut across. 



The flowers are pollinated by long-tongued 



bees. The anthers open by slits on their inner 



faces, and the pollen, which is loose and dry 



(not sticky as in most insect-pollinated flowers), 



falls into the cavity ( "pollen- box "), which 



lies above the ovary and is roofed in by the 



five anther-scales. The pollen can only escape 



from the "box," through the space between 



the tips of the scales and the upper part of 



the style, when the projecting style- tip is 



moved about. A bee enters the flower, pokes 



its tongue into the spur in search of honey, 



rubs against the stigma, shakes the curved 



style, and causes the pollen to drop on to its 



head, at the same time placing on the stigma any pollen it has brought 



from a previously visited flower. 



SEPALS 



Fig. 84. Longitudinal Section of Flower of 

 Garden Pansy. 



SPUR 



Fig. 85. Floral Diagram 

 of Violet. 



