2030 A TEXTBOOK OF THEORETICAL BOTANY 



florus) and the rare Gladiolus illyricus are almost the only representatives. 

 Species of Iris, Gladiolus, Freesia and Crocus are, however, very widely 

 cultivated and at first sight bear only a superficial resemblance to one 

 another. 



The family is essentially one which thrives best in a dry climate where 

 there is plenty of sun to ripen the corms or rhizomes and it is for this reason 

 most common in the warmer and drier parts of the southern hemisphere. 



The plants are mostly perennial herbs growing from a corm or rhizome, 

 occasionally from a bulb. A few are shrubby. The leaves are radical but in 

 a few species there may be cauline leaves in addition. 



The inflorescence is usually a small cyme or a compound inflores- 

 cence of several small cymes. In Gladiolus and Freesia the lateral cymes are 

 reduced to single flowers each with a bract, thus producing essentially a 

 spike. In some genera the flowers are terminal, as in the Crocus. 



The flowers (Fig. 1969) are hermaphrodite, actinomorphic or some- 

 times zygomorphic, usually very ornamental and sometimes beautifully 

 mottled or spotted, 



O 



Fig. 1969. — Floral diagram of 

 Iris pseiidaconis Iridaceae. 



The perianth (Fig. 1970) is composed of six segments in two whorls, 

 usually petaloid and superior. 



The androecium consists of three epipetalous stamens which are 

 developed opposite the outer perianth segments. The filaments are free or 

 partly connate. Anthers with two lobes opening extrorsely by longitudinal 

 slits. 



The gynoecium is tricarpellary and syncarpous. The ovary is inferior, 

 trilocular, with axile placentation or occasionally unilocular with parietal 

 placentation. 



The style is slender, three-lobed in the upper part and branched in 

 various ways but in Iris it is expanded into three large petaloid lobes. The 

 ovules are usually numerous and anatropous. 



The fruit is a capsule dehiscing loculicidally by valves, often with a 

 marked circular scar at the top. 



