and Laboratory Methods. '2G9I 



8. From prepared slide draw an eight-celled female gametophyte (embryo 

 sac), showing the three antipodal cells, the two polar nuclei, the oosphere, and 

 the two synergids. 



9. From prepared slide draw a mature, seven-celled female gametophyte, 

 showing the conjugation of the polar cells to form the definitive cell. 



10. From prepared slide draw an embryosac with endosperm cells, which 

 have come from the division of the definitive cell, and with young embryo, con- 

 sisting of the embryo proper, the suspensor cells and the large, vesicular, basal, 

 suspensor cell. Note that the conjugation of the polar cells and the subsequent 

 development of the endosperm are entirely new phenomena, nothing similar 

 occurring in plants below the angiosperms. In many angiosperms the second 

 sperm cell from the pollentube comes down and unites with the definitive cell pro- 

 ducing a triple fusion. 



11. Carefully remove a mature embryo from the seed and sketch under low 

 power, showing the single cotyledon, the lateral plumule and the radicle. 



12. Note that in this plant the seed remains in the ovulary. Make a dia- 

 gram showing position of the carpel wall, the integuments of the ovule, the 

 endosperm, and the embryo. 



13. Sketch a young seedling. 



14. Make a diagram in the notes showing the general life cycle of an angio- 

 sperm. See Fig. 14. 



LXXIX. Sedum acre L. Wall-pepper. 



Class, Dicotyledones. Order, Rosales. Family, Crassulacese. 



Many of the sedums grow well in greenhouses and in window gardens. 

 They usually bloom abundantly in the spring and the above or any other species 

 will be found suitable. 



1. Make a careful drawing of the flower and describe the character of the 

 different parts. 



2. Make drawings of the calyx, the corolla, the androecium and the gynce- 

 cium. 



3. Answer the following questions correctly : 



Is the flower hypogynous, perigynous, or epigynous ? 



Is it tetracyclic or pentacyclic ? 



Are the circles or whorls trimerous, tetramerous or pentamerous ? 



Are the organs of any whorl or set united or partly united ? 



Is the flower isocarpic or anisocarpic ? 



Is it actinomorphic, isobilateral, zygomorphic, or nonsymmetrical. 



4. Make two diagrams showing the true condition of the flower as learned 

 above. See Fig. 15 a. and b. 



LXXX. Trillimn grandifloriim (Mx.) Salisb. Large-flowered Wake-robin. 

 Class, Monocotyledones. Order, Liliales. Family, Liliacene. 

 The large-fiowered wake-robin grows in rich woods and blooms in April and 

 May. 



1. Make a sketch of the entire plant, showing the flower, leaves, and short 



