ROOTS OF MOSSES. 



29 



we there find, in correspondence with the simpler organisation of the whole, 

 roots also of simpler structure — rudimentary forms of root in which, however, the 

 essential physiological properties of true roots appear quite as evident as in them ; 

 it is therefore, though unimportant in itself, a logical error to distinguish these 

 organs of the Mosses and Algae with a special term as Rhizoids, since it must be 

 the aim of comparative organography to name alike -organs which are alike in 

 their nature. 



Meanwhile, with regard to this matter also a few examples must suflace. 

 Let us turn first to the true Mosses', which come so near to the vascular 

 plants in their shoot formation. From 

 the asexually produced reproductive 

 cell (the spore) of a moss, there arises 

 not immediately the proper moss-plant, 

 but a much simpler plantlet, con- 

 sisting of jointed and much-branched 

 cell filaments, the so-called Protonema. 

 Already in the germination, and yet 

 more in the further growth of this, the 

 contrast of shoot and root comes out 

 distinctly. While at the one end of the 

 germinating spore a filament containing 

 chlorophyll becomes developed, ascend- 

 ing above the substratum or cieeping on 

 its siu-face, with branches which in many 

 respects remind us of leaves, there ap- 

 pears from the other end of the spore a 

 thread devoid of chlorophyll, which bores 

 forthwith into the substratum, in certain 

 respects comparable to a tap-root, and 

 producing, like this, a branch-system of 

 roots. 



As, however, even in the vascular 

 plants the primary root usually remains 

 feeble, and becomes replaced by later 

 ones arising from the stem, so also on 

 the protonema of the moss, roots arise 

 here and there from the creeping shoot- 

 axes, as from the creeping shoots of vascular plants. At the same time there 

 arise from the protonema-shoots the proper moss-stems furnished with leaves ; 

 a process which corresponds to the formation of flowering leaf-shoots from the 

 rhizomes and stolons of vascular plants. Out of the shoot- axes of this moss-stem, 

 fresh root-fibres now arise, either from the basal parts only, just as in the Maize 



FIG. 19. — A young plantlet (w) ot a Moss ISarbultz) with roots 

 (A), the forward growing ends of which (tw) are attached to granules 

 of soil ; at ^, a superficial root is putting out branches containing 

 chlorophyll fi. e. protonema) ; at ifr, a tuberous bud is situated on a 

 subterranean root ; B the latter more strongly magnified (^ X 20 ; 

 B X 300). 



' Compare Schimper, Recherches anatomiques et physiologiques stir les Mousses, S'rassburg, 

 1848 ; Sachs, Lehrb. d. Bot. Cap. Laubmoose; Hermann Miiller, in Arbeiten des Bot. Inst. Wiirz- 

 burg, I. p. 475. 



