64 



THE GENEKAL DEVELOPMENT OP PLANTS, 



ramified cell, intricately interlaced or compacted, and forming dense 

 masses of considerable size and of definite shapes. 



104. While in these cases the ramifications of the cell imitate, or 

 as it were foreshadow, the stem and branches of higher organized 

 plants, we have in Botrydium (Fig. 88) a cell whose ramifications 

 resemble and perform the functions of a root. This consists of an 

 enlarged cell, which elongates and ramifies downwards, the slender 

 branches penetrating the loose and damp soil on which the plant grows, 

 exactly in the manner of a subdivided root. Meanwhile, a crop of 

 spores or rudimentary new cells is produced, by original cell-forma- 

 tion (29), in the liquid contents of the mother-cell: these, escaping 

 when that decays or bursts, grow into similar plants, in the manner 

 shown by Fig. 8G, 87. The spores by which Vaucheria is propagated 

 originate in a somewhat different way. When about to fructify, the 

 apex of a branch enlarges, its green contents thicken, separate from 

 those below, condense into a rounded mass, which acquires a coat of 

 protoplasm (Fig. 89, a) : the sac in which it was formed soon bursts 

 open, and the new-born spore escajjes into the water (Fig. 90). It 

 moves about freely for some hours (678), when a coat of cellulose is 

 formed upon its surface, converting it into a true cell, which soon 



FIG. 85-87. Botrydium Wallrothii in ita development, and with new cells forming within ; 

 after KUtzing : 85. the cell still spherical : 86, pointing into a tube below : 87, the tube pro- 

 longed and branched : all much magnified. 



I'lG. 88. Botrydium argillaceum, after Endlicher; the full-grown plant, magnified. 



FIG. 89. Vaucheria clavata, enlarged; a, a spore formed in the enlarged apex of that 

 branch. 90. End of the branch, more magnified, with the spore escaped from the burst apex. 



FIG. 91. Bryopsis plumosa ; summit of a stem with its branohlets, much enlarged. 



