PLANT DEVELOPMENT CONTINUED. 



45 



cone (Fig. 46). Here the ovules, instead of being numer- 

 ous and erect on each scale (as 

 in the Cypresses), are single 

 or in pairs, and inverted on 

 the scale (Fig. 46, b, c), the 

 micropyle pointing downward. 

 The cotyledons are often di- 

 vided. 



The Scotch Pine has five, six, or 

 seven cotyledons (Fig. 47, E, K); 

 the Cedar of Lehajion (Pig. 47, D) 

 has six. The Italian Stone Pine 

 (so called from its large edible stone 

 or seed) has cotyledons with 9 to 



11 divisions; when the ripe kernel -p,^ ,„ „ „ „.,,,, 



is split, they separate in the form of a ceSf ; ^'aC^^Zl^X'Zl", 'fTcS 

 hand ; this the peasants of the South ^^'^ 2 inverted winged ovules ; r. sfnirin 

 of France call " La main de Dieu,'' °''"^*'' separated from scale. 



c, single 



the Hand of God ; they use it as a remedy for intermittent fevers. 



Fig. 47. — A, pollen-grain of Cypress (Cupresms sem- 

 pervirem), sbowing the extiiie and intine, and the rudi- 

 mentary protliallus as a small cell cut off at one end from the main cell. 

 B, pollen-grain of Ceratozninia longifoHa emitting its intine in the form 

 of a pollen-tube, p«, which escapes through the ruptured extine e ; 

 y, rudimentary prothallus. C, diagram of vert section of ovule of 

 Pinue mjlvesiris: i, integument, or testa; w, micropyle; &, nucleus; e, 

 embryo-sac; c, c, embryonic vesicles; h, neclt of one of them; j), ex- 

 tine of poUeu-grains ; s, pollen-tubes. D, embryo of ripe sd. of Cedar 

 of Lebanon (C lAhani), half of sd. cut away, showing perisperm and testa. E, 

 emb. of Scotch Pine (P. sylveBti-is), sd. attached. F, same, with plumule. E and P 

 sprouting. 



77. Fertilization of Gymnosperms is verysimple. There 



