Organography of plants, especially of the archegoniatae and spermaphyta . to the outsideby a narrow slit above thepoint of the first foliage-leaf. As the young seedlingshows (Fig. 276, II), thesheath develops in germina-tion also very greatly inthe first instance, and theelongation of its zone of incr>rfir»n ivHiVIt in Ficr o-if\ FiG. 276. Cyperus alternifolius. Erabr\-o and germination. I. msertlOn, W men in r Ig. 2/ O, cmbrjo in longitudinal section. Co, cotyledon ; 5. cotylar sheath ; T i*c in/^iVot/r^rl K-ir fVip> Ar&^f^A •^- S* foliage-leaf; \\\ primordium of a root upon which at El
Organography of plants, especially of the archegoniatae and spermaphyta . to the outsideby a narrow slit above thepoint of the first foliage-leaf. As the young seedlingshows (Fig. 276, II), thesheath develops in germina-tion also very greatly inthe first instance, and theelongation of its zone of incr>rfir»n ivHiVIt in Ficr o-if\ FiG. 276. Cyperus alternifolius. Erabr\-o and germination. I. msertlOn, W men in r Ig. 2/ O, cmbrjo in longitudinal section. Co, cotyledon ; 5. cotylar sheath ; T i*c in/^iVot/r^rl K-ir fVip> Ar&^f^A •^- S* foliage-leaf; \\\ primordium of a root upon which at El 1, 13 niun-ctLC-U vjy Liic UULLCU is the remains of the suspensor. The zone between the dotted lines is WnP. tli^ m^co/~r»fi-1 ^^^^ \sV\c\\ forms the mesocotyl. II, and III, young and older line, lOimS me meSOCOtyi seedling plants. Lettering as m I. The seed-coat is still attached ,,.t,:. ;.,^^ ^U^ ^4^^.,, U,,J to the seedling. In 11 the cotylar sheath is not yet ruptured. L\, which brings the stem-bud second leaf; J/,-, mesocotyl. All 414 TRANSFORMED LEAVES above the soil, where finally the cotylar sheath is ruptured at its tip(Fig. 276, III). Scirpus laeustris. A further example of this second case amongst theCyperaceae is furnished by Scirpus laeustris (Fig. 277). In general, we maysay that the cotylar sheath is the more developed in the seed, the earlier andthe more massively it has to be developed in the germination. In Scirpuslaeustris this is seen in marked degree. The sheath becomes green at thetip, and forms there, apparently, a second lamina—the first being the broadshield-like portion forming the hypogeous haustorium, and lying apparentlyover against the stem-bud. The great development of the sheath in theseed has given rise to misinterpretation. The portion marked «, in Fig. 277,is by most authors called the radicle. The root, r, here, as in other
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