730 BOTANY PART n 



furnish Saffron. Other species are cultivated as ornamental plants. Iris, leaves 

 overlapping in two ranks. The leaf-sheath surrounds the thick fleshy rhizome, 

 while the sword-shaped blade stands erect and has its two lateral surfaces alike 

 (Fig. 807). Outer perianth segments bent downwards, inner erect. The three 

 anthers are roofed over by the three leaf-like styles. In Gladiolus the flowers are 

 dorsiventral, and the dissimilarity of the perianth leaves is more marked. 



Family 5. Bromeliaceae. Mostly epiphytes ; flowers hermaphrodite. Limited 

 to tropical and sub-tropical parts of America. The leaves are in rosettes and 

 are typically xerophytic ; in the forms which grow in the soil they are spiny. 

 Ananassa sativa is cultivated ; its inflorescence forms the Pineapple. 



Order 3. Enantioblastae 



Characterised by the atropous ovules ; the embryo is at the summit of the 

 endosperm at the opposite end from the hilum. 



Family. Commelinaceae. Tropical and sub-tropical. Perianth developed as 

 calyx and corolla. Commelina, Tradescantia. The hairs of the stamens afford 

 well-known objects for the study of movements of protoplasm and nuclear 

 divisions. 



(b) Flowers more or less reduced 

 Order 4. Glumiflorae 



This order consists entirely of annual or perennial plants of grass- 

 like habit. It is distributed over the whole surface of the earth. 

 A woody stem only appears in the genus Bambusa. The association 

 in more or less complex inflorescences of numerous flowers, which lack 

 a proper perianth but are enclosed by scaly bracts (glumes), is a 

 common character of the order. The perianth is either completely 

 wanting or reduced to a series of scales or bristles. The inner whorl 

 of stamens is also usually wanting, The superior ovary is always 

 unilocular and contains only one ovule ; it is formed of three 

 (Cyperaceae), two (some Carices), or of a single carpel (Gramineae). 

 The large size and feathery and papillose form of the stigmas stand 

 in relation to the wind, pollination. Fruits indehiscent. 



Family 1. Cyperaceae. The Sedges are characterised by their 

 triangular stems, which are usually neither swollen at the nodes nor 

 hollow, and by their closed leaf-sheaths. The flowers are unisexual and 

 then usually monoecious (Carex) or are hermaphrodite as in the majority 

 of the genera ; ovary formed of two or three carpels with an erect, 

 basal, anatropous ovule. Pericarp not coherent with the seed-coat ; 

 embryo small, surrounded by the endosperm. 



The genera Cyperus, Scirpus, and Eriophorum have hermaphrodite flowers. 

 Fig. 808 represents a plant of Scirpus setaceus, which is an annual, in flower. 

 Leaves rigid, channelled above. Fertile shoots with the uppermost internode 

 elongated. Spikes 1-3, terminal ; enclosed by imbricating bracts and displaced 

 to one side by the subtending bract, the line of which continues that of 



