380 



BOTANY 



In the Iridaceae (Iris, Gladiolus, Sisyrinchium, etc.) the flower 

 (Figs. 353, 369) is much like that of the Amaryllidaceae, but the 

 stamens are reduced to a single whorl of three. Some of these are 

 otherwise specialized, the peculiar form of the flower in Iris being 

 associated with pollination by special insects, and the same is true 

 of the zygomorphic flowers of Gladiolus. 



The most highly specialized monocotyledonous flowers are found in 

 the Scitamineae and Orchidaceae. In Canna (Fig. 372) the epigynous 



FIG. 352. A-C, Arisasma triphyllum. 

 A, inflorescence, the spathe cut away 

 at the side to show the pistillate 

 flowers,. # (X). B, pistillate flower 

 cat longitudinally. C, male flowers. 

 D, Lemna minor, pistillate flower, 

 cut longitudinally and enlarged , show- 

 ing ovule, o. E, Sparganium simplex, 

 two pistillate flowers enlarged ; in 

 one the perianth leaves, per, have 

 been removed. 



FIG. 353. A, actinomorphic flower 

 of Sisyrinchium bellum (X 1). 

 B, zygomorphic flower of Gladiolus 

 sp ; o, inferior ovary. 



flower has all the stamens present, 

 but only one is fertile, the others 

 being changed to petal-like " Sta- 

 minodia," the conspicuous part of 

 the flower. 



In the Orchidaceae the stamens are reduced to a single one in most 

 cases, and this is united with the upper part of the pistil into the 

 peculiar structure known as the gynostemium or column (Figs. 373, 

 374). The flowers are strongly zygomorphic, and with few excep- 

 tions they are absolutely dependent upon insects for pollination. 



The flowers of the Monocotyledons may be borne singly, as in some 

 species of Narcissus and Tulip, but more commonly they are in inflo- 

 rescences of various kinds, which sometimes are of enormous size, as in 

 the Century-plant (Agave Americana), and many Palms, Yucca, etc. 



