. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. 160 FERTILIZATION. first expands infx) a proper cell, and is usually attached to the wall of the sac near the micropyle. It then di- vides itself transversely, becoming two cells; the upper elongates either with or without subdivision, forming a filament (suspensor); the lower cell enlarges by subdi- vision, first spherically, and afterwards the little mass begins to take form according to the species, showing cotyledons, pl
. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. 160 FERTILIZATION. first expands infx) a proper cell, and is usually attached to the wall of the sac near the micropyle. It then di- vides itself transversely, becoming two cells; the upper elongates either with or without subdivision, forming a filament (suspensor); the lower cell enlarges by subdi- vision, first spherically, and afterwards the little mass begins to take form according to the species, showing cotyledons, plumule, etc., until fully developed into the embryo. 759. Schleiden's vie"w. Owing to the ex- treme difficulty of observation in this minute field, different views of this process have been advanced. That of Sohleiden should not be overlooked. He maintains that the end of the pollen tube actually penetrates the sac and itself becomes the embryonic cell. The pollen grain is in this view the primitive cell, and is itself quickened into development by the contents of 608, Growth of the eml ryo .i v in Hippuris vulgaris. Theferti-the embryo sac. tized cell has divided itsellin- ^ FERTILIZATION IN THE CONIFERS to several, of which c, &, con- stitute the sw^mso)-attached WJicre no style or stigma exists, as in the Coni- totheapexofthesac; a,em-j;.,,. ^.j,^, âg,^ fjj|,^ directly into the micTopyle Dryo dividing iQto 2, then into J- , . i ⢠i of the naked ovule and its tubes settle mto the 'tissue of the i cells. 761. Chemical' changes in germina- tion. The ovule matures with the com- pletion of the embryo, and passes into the fixed state of the seed in which the embryo sleeps. A store of nutritive matter, starch, gluten, etc., is thought- fully provided in the seed for the use of the young plant in germination, until its root has gained fast hold of the soil. 762. The changes which occdr in THE SEED at the recommencement of -ââ n i <â tt- i * â , 609, Ovul
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