xviii CONTENTS. 



CHAPTER XXXIII. 



MORPHOLOGY OF THE ANGIOSPERMS. TRILLIUM; DENTARIA. 



Trillium, 440. General appearance, 440. Parts of the flower, 

 calyx, 441. Corolla, 442. Andrcecium, 443. The stamen a 

 sporophyll, 444. Gynoecium, 445. Transformation of the 

 flower of trillium, 446. Dentaria, 447. General appear- 

 ance, 447. Parts of the flower, 448 page 221 



CHAPTER XXXIV. 



GAMETOPHYTE AND SPOROPHYTE OF ANGIOSPERMS. 



Male prothaltium of angiosperms, 450. Macrospore and em- 

 bryo-sac, 453. Embryo-sac is the young female prothal- 

 lium, 445. Fertilization, 456. Fertilization in plants is 

 fundamentally the same as in animals, 457. Embryo, 458. 

 Endosperm the mature female prothallium, 459. Seed, 460. 

 Perisperm, 461. Presence or absence of endosperm in the 

 seed, 462. Sporophyte is prominent and highly developed, 

 463. The gametophyte once prominent has become degen- 

 erate, 464. Synopsis of members of the sporophyte in 

 angiosperms, 467. Table showing homologies of sporo- 

 phyte and gametophyte in angiosperms, 468 page 228 



CHAPTER XXXV. 



MORPHOLOGY OF THE NUCLEUS AND SIGNIFICANCE OF 

 GAMETOPHYTE AND SPOROPHYTE. 



Direct division of the nucleus, 470. Indirect division of the nu- 

 cleus, 471. Chromatin and linin of the nucleus, 472. The 

 chromatin skein, 473. Chromosomes, nuclear plate, and 

 nuclear spindle, 474. The number of chromosomes usually 

 the same in a given species throughout one phase of the 

 plant, 474. When fertilization takes place the number of 

 chromosomes is doubled in the embryo, 474^. Reduction of 

 the number of chromosomes in the nucleus, 475. Signifi- 

 cance of karyokinesis and reduction, 476. The gametophyte 

 may develop directly from the tissue of the sporophyte, 477. 

 The sporophyte may develop directly from the tissue of the 

 gametophyte, 478. Perhaps there is not a fundamental dif- 

 ference between the gametophyte and sporophyte, 479. page 239 



