F7RST GROUP. THALLOPHJ'TES. 



transverse septa, which lie far behind the growing apex and are oblique from the first. 

 The two adjacent cells are placed one against the other like the soles of two human feet 

 placed sole to sole. The branching proceeds only from the lower end of the upper cell 

 (Fi&- 33) B] > a protuberance is formed which is cut off by a septum and then 

 by further division produces several cells, which grow into branches ; these therefore 

 are placed in a tuft on one side. The tubes of the rhizoids vary in length from several 

 millimetres to more than two centimetres, and in breadth from one-fortieth to one-tenth 

 of a millimetre. 



The vegetative (asexual) multiplication of the Characeae proceeds for the most part 



from the nodes, and has three modifica- 

 tions: I. Tuber-like bodies, the so-called 



pi.%, "|PPr$% H h bulbils or amylum-stars of Char a stelli- 



gera; these are isolated subterranean 

 nodes with much-shortened leaf-whorls of 

 neat and regular construction, and with 

 their cells densely filled with starch and 

 other formative material ; shoots from 

 them develope into new plants. 2. Branches 

 ivith naked base of Pringsheim. These are 

 formed on old nodes of Chara of the pre- 

 vious year's growth, or on nodes cut from 

 the stem, in the axils not only of the 

 oldest but also of the younger leaves of a 

 whorl ; the chief difference between these 

 and normal branches is that the cortical 

 envelope is entirely or partially wanting 

 in the lower internode and in the first 

 whorl of leaves ; the cortical lobes which 

 descend from the first node of the branch 

 often separate from the internode and 

 grow free, curling upwards ; the leaves of 

 the lowest whorl often form no nodes. 

 3. Pro-embryonic branches. These grow 

 beside the branches with naked base from 

 the nodes of the stem, but they are essen- 

 tially distinct from them, their structure 

 being that of the pro-embryo which pro- 

 ceeds from the spore ; like the branches 

 with naked base, they have only been ob- 

 served on Chara fragilis and by Pring- 

 sheim. A cell of the stem-node grows 

 out into a tube, whose apex is cut off by 

 a septum ; the terminal cell elongates and 

 fresh divisions are formed in it, till the 

 apex of the pro-embryo consists at last of 

 a row of from three to six cells. A new 

 plant is developed from this pro-embryo, 

 just as from the pro-embryo produced by the germination of the oospore. Beneath the 

 apex of the pro-embryo (Fig. 34, C, ab] the tube swells, and the swollen part is cut oft 

 by a transverse wall, and forms a cell which Pringsheim terms the bud-rudiment 

 (Fig. 34, C, from a to d inclusively). This cell divides into a short upper and short 

 lower cell, with a middle one between them. The middle cell does not divide again, but 

 grows into a long tube. The two other cells are the stem-node (Fig. 34, a) and the 

 node from which rhizoids grow (Fig. 34, d). The stem-node divides first by a 



FlG. 34. Chara fragilis. A an entire pro-embryonic branch ; 

 i the lowest colourless cell beneath the node forming rhizoids ; 

 q the long cell which arises from the middle cell of the bud- 

 rudiment ; pt the apex of the pro-embryo ; at g is the false leaf- 

 whorl, TJ the bud of the second generation of the leafy plant. B 

 upper part of a younger pro-embryonic branch ; i, d, q as before, 

 * =// in A ; I, II, ///the young leaflets of the stem-node, v the 

 bud of the leafy stem. C still younger pro-embryonic branch ; 

 i, d, q, b as in B ; v the apical cell of the bud of the stem. 

 After Pringsheim ; magn. 170 times. 



