24 (iJJACK E. COOLEY ON 



4. The tliickriiiiiii- ol' tlic wiills is ;it first local in the culls between the chalaza and 

 the center of the seed. 



5. The process of thickening is gradual, the corners of the cells being affected 

 before the rest of the walls. 



6. Reserve cellulose in Iris is, while forming, easily afl'ccted by water, swelling, 

 losing its structure, and becoming a mucilaginous mass. 



7. This structureless mass is colored brown with iodine in potassium iodide- 



8. Before the process of thickening has reached the cells of the outer layers of the 

 endosperm, these cells contain proteids and crescent-shaped bodies, which are colored deep 

 red-brown with iodine. 



9. A close layer of cells containing oil with some layers of spongy cells forms the 

 inner integument which encloses the endosperm. 



Growth of the Seed of Poly<jon(i,luvi muUiJlonmi. 



The behavior of the reserve cellulose in seeds of Pohjijonatum multiflorum is in 

 some particulars different from that in seeds of Iris sibirica. On July 1, 1894, the 

 endosperm in many of the seeds of this species was completely formed, but the cell walls 

 were still unthickened. PI. G, fig. 2, illustrates this stage, though the sketch was made 

 from material (preserved in absolute alcohol and sulphur dioxide) which had been 

 collected at a later date, in another season. The nucleus is at n. It lies near the center 

 of the cells, contains several nucleoli, and from it threads of protoplasm reach toward 

 the walls in every direction. PL 6, fig. 1, represents a few cells of the endosperm during 

 the formation of the cell wall. 



When the endosperm cells are formed, they contain sugar in large amounts, as do 

 the cells of the integuments and the lleshy portions of the young bei'ry. Much oil is 

 present in the endosperm, but not so mueh..as in corresponding stages of Iris. PI. (1, fig. 

 3, shows a cell from material gathered, July 1, 1894; the oil has been aggregated with 

 chloral hydrate; n, nucleus; o, oil. 



The integuments do not contain so much tannin as those of Iris, and the oil-bearing 

 layer is not present. Sugar is present in the integuments and fieshy placentae, but no 

 starch is contained in the berry. 



A later stage of the seed shows starch-formers in a few cells of the endosperm near 

 the chalaza, and a few minute grains of starch are with difficulty detected. The walls 

 of the cells are coated with a layer of protoplasm, which contains small oily globules. 

 See PI. fi, fig. 4, n, nucleus, with stan-li grains in the neighborhood. 



Twelve days later, the thickenings of the walls had begun in the endosperm ; this 

 was in a V-shaped mass near the chalaza, with the i\-pex toward the center of the seed. 



