298 THE STORY OF PLANT LIFE 



"]"]. The Iris Group (Summary). 



{Introductory Volume^ p. 202.) 



Of the Order Iridacese there are eight hundred 

 species and fifty- seven genera. They are found in 

 the Tropical and Temperate parts of the world. A 

 large proportion belong to the South African and 

 Tropical American regions. Of British types there 

 are five genera : Romulea, Sisyrinchium, Crocus, Iris, 

 and Gladiolus. 



The affinities of the group are with the Orchid 

 Group and Snowdrop Group. 



They are perennial, herbaceous plants. There is 

 usually a sympodial epigeal rhizome or tuber, or bulb 

 or corm. 



The leaves are in two ranks, folded upon each other 

 lengthwise, and overlapping, or equitant, arranged on 

 opposite sides of the stem vertically, not horizontally, 

 flattened, sheathing the stem. 



The inflorescence is terminal, cymose. There may 

 be only one flower, as in the Crocus. The flowers 

 are regular or irregular, complete. The perianth is 

 superior, petaloid, tubular below, the six segments in 

 two rows, sometimes unequal, overlapping, sometimes 

 twisted, and persistent after flowering. There are 

 three stamens, which are epigynous, or inserted on 

 or opposite the outer perianth - segments. The 

 anthers open outwards, and are usually narrow. The 

 ovary is inferior, three-celled, with axile placentae, or 

 unilocular with parietal placentae. There is a single 



