28 GRACE E. COOLEY ON 



Fig. 10. JAoydin semlina, cells fmm the endospenii ; from material supiMisetl to be unripe, seeds falling from the 

 capsules; preserved in absolute alcohol; with iodine; starch at a nearly covers the nucleus, x 3.50. 



Fig. 11. Cells from the endosperm of seeds of Lloi/dia serotinn ; material as above ; contents of the cells removed 

 with chloral liydrate ; at a, the Hoors of the cells show the thin portions. xA'M. 



PLATE 2. 



Fig. 1. Section through the enclo.sperm of the seed of P.di/n iiiKtiim mnUiJbtrnin ; after lioilhig 1 niiii. in I! SO 

 (1 part IIoSOj, 5 part.s II.^O). The reserve celhdose is dis.solved. x :!.")0. 

 Fig. 2. The same, contents also removed, x 350. 

 Fif. 3. Section of the .seed of Tulipa ijesnerinwi, (hiring solution with weak, hot, sulphuric acid; treated with 



iodine. 



Figs. 4 and 5. Sections of ruli/ijomdam miiUiJUirnin seeds after twenty-four days' treatment with cold, weak IICI. 



x350. 



Fig. 6. Section of Polygonatura seed after eight hours' boiling in water. The section is tangential to the seed ; at 

 a, the surfaces of the cell walls appear, with the ends of the canals as pits. The canals do not always meet those in 

 the contiguous cells, from the obli(pie nature of the section, x 350. 



Fig. 7. The sketch represents tlie swollen appearance of the walls of the seeds of Irj.s pxewlwtrmi after eight 

 hours' boiling ; a, distorted wall ; '), contents of the cell, x 350. 



Fig. 8. Section thnmgli the nearly ripe endosperm cells of C mvallnrin innj(dl^. x 350. 



PLATE 3. 



Fig. 1. Section tlirongh the ripe seed of ridijiinnntiiiii, iiinUifioruiii. ; A, natural size; B, magnified. 



Fig. 2. Section through the embryo of P'Ai/ipiiiaf.ani muUljlirum ; before the protruding of the radicle. A, embryo, 

 slightly enlarged; a, cotyledon ; i, hypocotyl ; c. punctum vegetationis ; d, nascent vascular tissue; e, root-cap, containing 

 starch. B, region about the punctum vegetationis; d, cotyledon; h, nascent vascular tissue; c, punctum vegetationis; 

 fi, tissue containing starch formers, x 350. CJ, cells from the cotyledon, treated with chloral hydrate, and osmic acid : 

 n, nucleus; o, oil. x 350. 1), cells from below the vegetative cone; treated with absolute alcohol, mid with iodine; 

 n, nucleus ; s, starch-formers, x 350. 



Fig. 3. Section- of young plant of PolycjonaUiiu muUifiorani eight weeks after the planting of the seed. A, natural 

 size; B, enlarged. The section has been treated with ioilinc ; n, unaltered endosperm, red-brown with iodine; ft, cells 

 from which the reserve has been dissolved, colorless wiili iodiiLc; r, cotyledon with central vascular shaft well formed; 

 some starch in the cells, and oil in the layer of epithelium cells in contact with the endosperm ; d, portion of the coty- 

 ledon outside the .seed, wliich earlier enclosed the bud; c, young bud; /, young stem, cells gorged with .starch; <j, root- 

 hairs. 



Fig. 4. Younger .s(;edling of Voliitriiiatam iniUtiJi.orain somc'what more eidarged. Tlie cotyledon in this case is curiously 

 lobed; c, bud still enclosed in the sheathing cotyledon ; e, endosperm with luulissolved reserve cellulose ; d, endosperm with 

 reserve cellidose di.ssolved; a, layer of cells rich in oil; ft, cells containing starch. 



Fig. 5. Cells of endosperm from seecUiugof Poli/goiuUam. iiiidUjlimm, which are in contact witli the cotyledon ; e, cotyle- 

 don ; /, collapsed, exhausted cells ; {/. loose, nearly empty cells. At B, a. the cell walls are distorted by pressure from the 

 growing cotyledon, x 350. 



Fig. (>. Portion of the endosperm of the .seed of Pidi/i/Diudiiin »(H//(riyra/«, eleven weeks after planting. Tlie irregular 

 solution of the reserve of the walls is shown ; o, oil ; n, nucleus. Small globules of oil, in contact with the wall, are shown. 

 X 350. 



Fig. 7. Portion of the seed of Pidi/i/onidnm iiiidUflundn fVJ:ht weeks after planting. 1. Cells of the cotyledon, contain- 

 ing much oil in the outer row ; a. nucleus; n, inner cells, containing starch formers with starch. 2. Mass of collapsed cells. 

 3. Cells from which the reserve is dissolved. 4. Cells which show the gradual and quite uniform solution of tlie reserve ; 

 6, gramdar aiul oily, reserve contents ; o, oil. x 3.50. 



PLATL 4. 



Fig. 1. Young seedUng of Iria pucudarnrns tour weeks after sowing the seed. A, a, seed with testa ; ft. petiole ; r. luuMiy 

 tip of petiole, which lirst appears above the ground ; d. sheathing portion of the petiole; e, stem; /, root ; ;/, first leaf above 

 the soil. Natural size. B, section of the seed from the same seedling; a, cotyledon filled with starch; 6, endosperm with 

 thickened walls; c. endosperm cells, from which the reserve is dissolved. Natural size. 



Fig. 2. Section of seedling of Iris pxciidiirorufi. still in the soil (with ioiline) ; a. endosperm ; ft, cotyledon ; <■, petiole of 

 the same; d, horny tip; e. .sheathing portion ; /', bud ; ;/, liyp ic.ityl. Stareli is seen in the sheathing part of the petiole in the 

 bud, and in the hypocotyl. Natur.al size. 



