Text-book of botany, morphological and physiological . right and left row of segments oflifferent ages; in Fig. 290 a an internode is formed of the segment Hon the rightide, of the anterior half of the older segment, G, and of the posterior half of theounger segment, /, on the left side; the next internode is the product of the whole)f the left segment, L and of the tw^o halves of K and H lying to the right; thentermediate nodal disc which forms the leaves w, Z^, L^ consists, on the otherland, of the anterior half of the left older segment / and of the posterior half of theight younger segment
Text-book of botany, morphological and physiological . right and left row of segments oflifferent ages; in Fig. 290 a an internode is formed of the segment Hon the rightide, of the anterior half of the older segment, G, and of the posterior half of theounger segment, /, on the left side; the next internode is the product of the whole)f the left segment, L and of the tw^o halves of K and H lying to the right; thentermediate nodal disc which forms the leaves w, Z^, L^ consists, on the otherland, of the anterior half of the left older segment / and of the posterior half of theight younger segment K; in the preceding and succeeding node the relationshipsire the same, right and left being transposed. In each whorl the submerged leafs the oldest, the one further from it of the two aerial leaves the second; the nearerlerial leaf is the last formed. Each leaf arises from a cell of definite position, RHIZOCARPEM. 39^ which becomes arched outwards (Fig. 291, 7y,Zj, ZJ, and, becoming the apical cellof the leaf, forms a row of segments on each =01—Apex of the horizontal floating stem of Salvinia (after Pringsheim); A ventral side, Adorsal side,C transverse section of the long vegetative cone, .VS apical cell of the stem, j* its last septum, iv submerged leaf,Z its lateral teeth, /. /. aerial leaves, h ft hairs. In Marsilea the apical cell of the embryo is so placed that dorsal and ventralsegments in two rows are at first formed from it by walls inclined upwards anddownwards ; the dorsal median leaf also proceeds from the first dorsal a differcnt arrangement is soon produced as the plant increases in strength;the apical cell of the stem forms segments arranged in three rows with a \ diver-gence, and in such a manner that one row of segments comes to lie below (ven-trally), while the two other rows form the dorsal side of the stem ; the ventral sideof the stem forms roots in strictly acropetal succession, the youngest being foundnear the apex of the ste
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
