The Encyclopaedia Britannica; .. A dictionary of arts, sciences and general literature . somespecies of Macuna and Dolichos, extending along a largeportion of the edge of the seed ; and it frequently exhibitsmarked colours, being black in the Bean, white in manyspecies of Phaseolus, «fec. The micropyle (fig. 308, m) ofthe seed, with its exostome and endostome, may be recog-nizable by the naked eye, as in the Pea and Bean , &c., or it may be very minute or microscopic. Itindicates the true apex of the seed, and is important asmarking the point to which the root of the embryo iadirecte
The Encyclopaedia Britannica; .. A dictionary of arts, sciences and general literature . somespecies of Macuna and Dolichos, extending along a largeportion of the edge of the seed ; and it frequently exhibitsmarked colours, being black in the Bean, white in manyspecies of Phaseolus, «fec. The micropyle (fig. 308, m) ofthe seed, with its exostome and endostome, may be recog-nizable by the naked eye, as in the Pea and Bean , &c., or it may be very minute or microscopic. Itindicates the true apex of the seed, and is important asmarking the point to which the root of the embryo iadirected. At the micropyle in the Bean ia observed asmall process of integument, which, when the young plantsprouts, is pushed up like a lid, and is called chalaza (fig. 311, ch) is often of a different colour froiathe rest of the seed. In the Orange (fig. 313) it is of colour, and is easily recognized at one endof the seed when the integuments are carefully anatropal seeds the raphe forms a distinct ridge alon^one side of the seed (iig. 314).. Fig. 310. Fig. 311. Fig. 313. Fig. 310.—Seed of Fir (Pinvs), with a menibranous appendage » to the testacalled a wing. The seed is said to be wintred. Fig. 311,—Voung anatropal seed of the Water-lily (XpmpTtcn alba)^ cnlverticaliy. It is attached to the placenta by the funiculus or umbilical cord/,cellular prolongations from which form an aril a a. The ves^ia of the con] areprolonged to the basi of the nucleus n hf moanB of tho raphe r, composed ofcells and spiral Tess.»!3. The base of the nucleus is indicated by the chalcia-rh, while the apex ia ut the micropyle m. Tho covering of the seed is marltcili. n is the nucleus or perisperm, surronnded by its covering, and enclosing «, in which the endosperm is formed. The embryo e, with Itssuspensor, is contained in tho sac, the radicle pointing to the micropyle m. Fio, .112.—Arillode a. ^r false aril, of the Spindle-tree {£
Size: 1920px × 1301px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectencyclo, bookyear1902
