BROMELIACE^E 571 



cotyledon remains in the seed, forming the absorbent organ ; 

 the other emerges and forms a short sheath. The second 

 leaf emerges from the top of this sheath. 



IRIDE^E. 



Benth. et Hook. Gen. PL iii. 681. 



Fruit and Seed. The ovary is inferior and three-celled 

 with axile placentas, or very rarely, as in Hermodactylus, one- 

 celled with three parietal placentas. The ovules are usually 

 numerous in each cell, rarely reduced to one or two ; they are 

 anatropous. The fruit is a globose, obovoid, oblong or rarely 

 linear capsule, with a loculicidal dehiscence. Sometimes, 

 sa in Tigridia, Rigidella, and Herbertia, the top protrudes 

 beyond the perianth-tube, leaving a free operculum at the 

 bottom of which the dehiscence stops at any rate for a time. 

 The seeds are few or numerous, superposed in two series, 

 rarely solitary in each cell with short, often very short funicles, 

 and a strophiole. They vary much in shape, and may be 

 globose or generally angular by mutual pressure, but some- 

 times flattened. Variations occur even in the same genus, 

 thus Gladiolus segetum has globose seeds, while in the very 

 closely allied G. byzantinus they are flat. The testa is mem- 

 branous or slightly thickened and spongy. The endosperm is 

 horny and fills the seed. The small embryo is completely 

 enclosed in the endosperm at a little distance from the hilum. 



Germination. We may distinguish three types character- 

 ised by differences in form and behaviour of the cotyledon. 

 The first, according to Klebs, 1 is represented by Iris Pseud- 

 acorus and Ixia crateroides. Here, as in the two following 

 types, the primary root is the first to emerge from the seed- 

 ling, and grows rapidly downwards. The hypocotyl is very 

 slightly developed, but the lower end of the cotyledon elon- 

 gates at an early period of germination drawing out of the seed 

 the plumule which is enclosed in its sheathing base. The 



1 Loc. cit. pp. 564-5, fig. 11. 



