. College botany; structure, physiology and economics of plants. Botany. 96 COLLEGE BOTANY inverted ovale, of which the violet is an example—^the ovule is inverted and the stem or funicle extends the full length, as the raphe (Fig. 71). The ovules (Fig. 72), which are borne within the ovary, are. Fig. Tl.^Types of ovules; (a) orthrotropous, (6) campylotropoua, (c) amphitropoua, {d) anatropous. to develop into the seeds. Each mature ovule is composed of a mass of cells, which is known as the nucellus, and is siirrounded by one or usually two integuments, which are to become the seed coats (Fig.
. College botany; structure, physiology and economics of plants. Botany. 96 COLLEGE BOTANY inverted ovale, of which the violet is an example—^the ovule is inverted and the stem or funicle extends the full length, as the raphe (Fig. 71). The ovules (Fig. 72), which are borne within the ovary, are. Fig. Tl.^Types of ovules; (a) orthrotropous, (6) campylotropoua, (c) amphitropoua, {d) anatropous. to develop into the seeds. Each mature ovule is composed of a mass of cells, which is known as the nucellus, and is siirrounded by one or usually two integuments, which are to become the seed coats (Fig. 73). The micopyle is a very small opening in the int-eguments through which the pollen tube penetrates to' the nucellus. Thp other parts of the O'Vule are the chalaza, or point of union between the nucellus and integu- ments ; the hilurrij, or point where the ovule is at- tached to the ovary wall by meansi of a short stem-like structure known as the funicle or funiculus; and the raphe, which is the exten- sion of the funiculus along the side of the ovule. An embryo sac," consisting of eight nuclei, is formed in the nucellus near the micropyle m^a'ti J'i7n?Sn"I (^^g^- '^^ and 74). In the mature eahbryo sac the fng developing ovute" eight uuclei are so grouped that there are three at each end of the sac and two in the central pai't. The three nuclei ^t the micropylar end of the embryo sac constitute the egg * The formation of this embryo sac will be explained in Chapter Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Cook, Melville Thurston, 1869-1952. Philadelphia and London, J. B. Lippincott Company
Size: 2129px × 1174px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1920
