GLOSSARY AND INDEX. 277 



hypogynous, inserted beneath the ovary, 189. 



imbricated, overlapping and breaking joints, as the scales of an invo- 

 lucre, 50. 



indigenous, native, not introduced, 184. 



indusium (pi. indusia) , the (usually membranaceous) covering of a sorus 

 or fruit-cluster in ferns, 131. 



inferior, inserted below some other organ ; the calyx is inferior and the 

 ovary superior when the former grows from beneath and is free from 

 the latter, 90 ; the inferior side of a flower is the one away from the 

 axis of inflorescence. 



inflorescence, the arrangement of flowers on the axis that bears them ; 

 any foi-m of flower-cluster. 



intercellular, lying between neighboring cells. 



intemode, the portion of a stem lying between two nodes. 



inulin, a substance having the same elementary composition as starch, 

 which it replaces in various Compositse, 34, 49. 



involucel, the whorl of bractlets subtending a partial inflorescence, 224. 



involucre, the whorl of bracts subtending a single flovver as in the anem- 

 one, or an inflorescence as in the dandelion, 188, 224, 256. 



keel, the keel-shaped structure formed by the union of the two lower 

 petals of a papilionaceous flower, 197. 



labellmn, the lip-like, or variously modified, lower petal of an orchid. It 

 is really the upper or posterior petal, the flower having been twisted 

 through 180° in the course of its development, 176. 



lacuna (pi. lacunoe), an opening or passage between cells, 138. 



lanceolate, having the general shape of the head of a lance or spear, 58. 



latex, the milky or colored fluid secreted by certain plants such as blood- 

 root, poppy, etc., 206. , 



leaf, 57. 



anatomy, 59, 69. 



arrangement, 59, 68. 



assimilation, 63, 71. 



description, 58. 



mechanical and conducting system, 62. 



modiflcations, 66, 73. 



physiology, 61, 71. 



protection, 61. 



respiration, 65, 72. 



transpiration, 71. 



