MetapJiyta L iliu m. 



157 



also occurs in a semi-crystalline form with which are asso- 

 ciated minute rounded masses of a double salt of magne- 

 sium and calcium termed globoids. All these bodies have 

 a nutritive value, to which reference will afterwards be 

 made. 



True crystals are also of common occurrence, especially 

 in the cell-sap. They are most commonly composed of 

 oxalate of lime, appearing in the form of short prisms or 



FIG. 75. ALEURONE. (Sachs.) 



A, seed of Pisnm sativum ; a, granular form of aleurone ; ?, intercellular 

 bpace; st, starch grains ; B, seed of Ricinns com mum's, crystalline form. 



long and slender needles known as raphides. Calcic carbo- 

 nate also occurs, but more rarely, and only, at least to any 

 extent, in a few groups of plants. Club-shaped masses of 

 calcic carbonate, pendent in certain cells of the leaf (e.g. of 

 Ficus elastica\ have been called cystoliths (% 77). 



The reproductive organs. We have already likened 

 the flower of the lily to a fir cone, and emphasised the mor- 

 phological identity of these two structures. We notice 



