RESERVE CELLULOSE. 29 



Fig. 3. Section of the seed of Iris pseudacorus when the pliiiit was three inches liigh ; a, cotyledon with much starch in 

 the cells ; b, vascular portion ; c, cells from which the reserve is dissolved, they still contain protoplasm ; on the edges of the 

 seed the walls are still thickened ; at d, the cells are displaced by cutting. Enlarged. 



Fig. 4. Isolated cell from the endosperm, examined in water ; a, nucleus ; b, oil drop, smaller ones and minute globules 

 near the walls ; the arrows indicate the direction of the streaming of the protoplasm, x 3-50. 



Fig. 5. Seedlings of Allium cepa at different stages ; n, seed ; b, cotyledon ; e, root; B, section of the seed of II ; most 

 of the food has been absorbed by the coiled tip of the cotyledon. Ill has freed itself from the seed on emerging from the 

 ground ; the cotyledon tip is not gi'een, and is about to wither away. Natural size. 



Fig. 6. Section of seed of Allium cepa as in fig. 5, II; a, cotyledon ; b, endosperm, with reserve dissolved from the walls ; 

 at c, the walls are still thickened. Enlarged. 



Fig. 7. A few cells from the seed of Allium cepa showing the method of solution ; a, undissolved reserve cellulo.se ; 

 ft, spaces between the cells, from which the reserve is dissolved. Not drawn to scale. 



Fig. 8. Cells of Allium cepa near the edge of the seed ; solution of the reserve is going on in tlie cells at a. x 350. 



PLATE 5. 



rig. 1. Section of the young seed of Iris sibirira, in the plane of the long axis; a, endosperm; b, embryo; e, layer of 

 close-set cells, containing oil drops ; d, chalaza, with a little starch in the cells ; e, cells of the outer integiiment, containing 

 chlorophyll, x 350. 



Fig. 2. Endosperm cells of Iris sibirica in the unripe seed ; the oil has been removed by absolute alcohol, x 350. 



Fig. 3. Cells from the close-set layer, in the integument ; each contains a greenisli yellow oil globule, x 350. 



Fig. 4. Cells of endosperm of Iris sibirica, at the stage when the tliickening of tlie walls is beginning. The section is in 

 absolute alcohol ; n. nucleus ; o, oil. 



Fig. 6. Cells from the outer layers of the endosperm of Iris sibirica, when only a slight amount of reserve cellulose is 

 present in the seed ; n, nucleus ; I, crescent shaped bodies, which, with the proteids about the nucleus, color red-brown 

 with iodine, x 350. 



Fig. 6. Cells from tlie same section as in fig. 4, after water has been applied, x 350. 



Fig. 7. Later stage in the swelling of the reserve cellulose in a seed from the sam3 as in fi j;s. 4 and 0. x 350. 



Fig. 8. A few cells from the endosperm of Iris sibirica when treated with chloroiodide zinc ; a, swollen masses of reserve 

 cellulose ; b, granular matters aggregated by the swelling of certain layers of the cell wall ; c, protoplasmic membrane still 

 extending to the original wall, x 350. 



Fig. Si. Cells from section of Iris sibirica seed which was cut transverse to tlie section in fig. 8. Treatment the same 

 as above, x 350. 



Fig. 10. Cells from the close set layer of llie integument, from seeds of Iris sibiric{i. two weeks later than in fig. 3. 

 x 3.5(1. 



Fig. 11. Cells from endosperm of Iris siliirica after the thickening of the walls lia,cl begun, x 350. 



PLATE 0. 



Fig. 1. Early stage of the endosperm cells of the seed of PDh/i/onatiim ;/inff(//")'H»), before the walls are formed. Witli 

 absolute alcohol and haematoxylin. x 350. 



Fig. 2. Cells of endosperm of Pulyrjonatum muliifl-orum, soon after formation ; n, nucleus with several nucleoli, x 350. 



Fig. 3. Cell of endosperm of Pidi/f/unatum multifiorum, before the thickening of the wall. The oil has been aggi'egated 

 by treatment with chloral hydrate ; o, oil ; n, nucleus, x 350. 



Fig. 4. Cells of the endosperm near the chalaza in a seed of Puliiijonatum, uiulUflorum, before any reserve cellulose 

 lias api^eared in the endosperm; n, nucleus, with starch-grains in the starch- formers, in the neighborhood; with 

 absolute alcohol and iodine, x 350. 



Fig. 5. Cells from the seed of Pnli/nonatiiin uiiillijh>riiiii. wiuii llie reserve cellulose first appears in the cell; », 

 nucleus ; a, reserve cellulose, x 350. 



Fig. G. Cells from the same endosperm as in fig. 5, where tlic tliickening lias proceeded farther. The two sketches 

 are from sections treated with ioilhie; ((.nucleus, x 3.5(1. 



Fig. 7. Cells from near the center of the endo.sperm of Calaidhas nicalis, in the later stages of ripening. 

 Only a few cells remain with unthickened walls; with iodine; n, nucleus; s. starch. At B the surface of some of 

 the cell walls is shown with points of less thickening at fi. x 350. 



Fig. 8. Section of nearly ripe seed of Ctilchicum autuinnale : a, embryo, containing starch; e. endosperm; c, crest of 

 the seed containing much starch. Enlarged. , 



Fig. 9. Endosperm cells of Colchicniii antuumaU: when the .seed is nearly ripe; with iodine; small intercellular 

 spaces occur at the corners, x 350. 



Fig. 10. Cell from the crest of the seed of C'olc/iirnm aatuuiimb: when nearly ripe; large starch grains are present 

 The section was treated with iodine, x 350. 



