36 



GLOSSARY OF 



(2) Conin, a tuft of hairs attached to the testa in some 

 seeds, as in Willow-herb and Milk-weed (Fig. 202). 



The coma must not be confounded with the pappus 

 of composite flowers ; the latter is attached to the fruit. 



(3) Wing, a thin expansion of the testa (Fig. 203). 

 But in the seeds of the Pine the wing splits off from the 

 scale upon which the seed grows (Fig. 168). 



Nucleus : the body of the seed within the integument, con- 

 taining 



^ (a) Eiubryo, the young plantlet as found in the seed. 

 This is made up of 



(1) Radicle, the rudimentary stem (Fig. 204). 



(2) 'Cotyledons, or Seed-leaves, the first leaves, often 

 thick and fleshy, as in the Bean (Fig. 205), but some- 

 times thin and leaf-like. 



(3) Plumule, the bud at the top of the radicle (Fig. 

 204). 



■'(b) Albumen ov Endosperm, y^hBn-prQ?,Qnt: nourishing 

 matter stored up outside the embryo, as shown in the 

 jhaded porti'on of Fig. 206, the light part in the centre 

 being the embrj-o. 



Kind. 



Dicotyledonous: having two cotyledons (Figs. 207, 208, 209). 



MON'OCOTYLEDOXOUS : having only one cotj-ledon (Figs. 210, 

 211, 212). 



PoLYCOTYLEDONOUS : having several cotyledons (Fig. 206). 

 This is rare. 



AcoTYLEDONOUS : having no cotj'ledons (rare). 

 Albuminous : having albumen or endosperna in addition to 

 the embryo (Figs. 206, 210). 



The following terms applj^ to the folding of the parts of the 

 embrj'o in dicotyledonous seeds : 



- (a) Accumhent, when tlie radicle is turned so as to 

 touch the edges of the cotyledons (Fig. 213). 



(b) Incumhent, when the radicle is turned so as to lie 

 against the back of. one cotyledon (Fig. 214). 



(c) Conduplicate, the same as incumbent with the 

 addition that the cotyledons are curved so as to partly 

 infold the radicle (Fig. 215). 



Nature and Use of the Parts of the Flower. 



All the parts of the flower are leaf-forms (pbyllomes), differing 

 from ordinary foliage-leaves, because their functions are 

 different. 



Fig. 202. 



cotyledon l ^^^&.»2vv'! 



■'radicle 

 Fitr. 201. 



cotyledon 



Fig. iOb. 



testa 



Figs. 207. 208. 209. 



Fig. 210. 



Fig. 21.3. 



Fig. 214. 



Fig. 215. 



