2034 A TEXTBOOK OF THEORETICAL BOTANY 



hybrids are commonly cultivated in this country. Most of them grow 

 from sympodial rhizomes which bear sheathing, isobilateral leaves 

 and small cymes of flowers in spathes. The perianth is petaloid, 

 the inner segments erect and the outer three segments usually 

 bending downwards. Opposite to them, and almost resting on them, 

 are the arching petaloid styles, under cover of which are the stamens 

 with their extrorse anthers. Just above the anthers on the outer 

 side of the style is a little flap of tissue whose upper surface is the stigma. 



The flowers are pollinated by bees which enter the flowers to reach 

 nectar secreted by the ovary. At their entry they come first into contact 

 with the stigma and there brush oflF any pollen they may have collected 

 from another flower. As the insect pushes further down it comes into con- 

 tact with the anther and recovers fresh pollen. Self-pollination is prevented 

 as the insect emerges, by the presence of the stigmatic flap. 



The capsule is usually large and opens by a loculicidal split to liberate a 

 large number of seeds which are flat and suitable for wind distribution. 

 Those of /. foetidissima and some others are round and brightly coloured, 

 red or orange, with fleshy coats. 



The cultivated Irises fall into two main groups; those which possess 

 rhizomes and those which develop from bulbs. Among the former type 

 are recognized the Bearded Iris in which the outer perianth segments (or 

 falls) have a thick band of fine hairs stretching down the middle of the lower 



Fig. 1973. — Iris sibirica. A garden form 

 with unusually large outer segments. 

 Possibly a hybrid. 



half, and the Beardless Iris in which the falls are hairless. The most 

 important species among the Bearded section is /. germanica which is the 

 original of many of our Bearded Flag Irises. Many varieties have been 



