14 



BOTANY 



classes resemble the higher plants in the formation and arrangement 

 of their members; Hydrolapathum sant/uim-iim (Fig. 9), for example, 

 as is indicated by its name, resembles a species of fittmex, and 

 affords an instructive illustration of the analogy of form existing 



Fia. 10. Kiccin ii<iitmi.< 

 (Nat. slice.') 



Fio. 11. Blasia piisillu. s, Sporogoiiiuin ; 

 r, rhizoids. (x 2.) 



between plants phylogenetically widely distinct from one another. 

 The progressive differentiation of the thallus of the Bryophyta 

 (Mosses and Liverworts)" presents an even closer parallel to the 



organisation of the higher plants. Within 

 the group of the Liverworts (Hepaticae) are 

 found ribbon-shaped forms and others that 

 show a division into distinct members. 

 Thus the thallus of fiiccia jlnitans (Fig. 

 10) is ribbon -shaped and dichotomously 

 branched, and its habit or general ap- 

 pearance recalls the Brown Alga Didyota 

 ilichotoma mentioned above (Fig. 8). Blasia 

 pusilla(Fig. 11) has marginal indentations 

 in its ribbon-shaped body. Lastly, Plagio- 

 chila asplenioides (Fig. 12), another Liver- 

 wort, has a distinction of stem-like and 

 leaf-like members which is completely 

 analogous to that exhibited by the most 

 highly organised plants. In spite of this 

 variety in external form, and the high 

 organisation that may be reached, the 

 body of these lower plants is termed a 

 thallus, and they are grouped together as 

 Thallophytes in contrast to the higher plants or Cormophytes. 



The Cormus. All plants, from the Pteridophtya or fern-like 

 plants onwards, may be grouped together as CORMOPHYTES. It 

 may be assumed that they have had a common origin, and that 



Ki<:. 1-.- -I'luiiiiK-Iiilit ax/ill 

 .--. S[>orogoiiiuin. (Xat. size.) 



