435 



Insect-visitors have frequently been observed in the 

 species of Ranunculus, usually small Diptera. 



III. Fruit- dispersal. The fruit is doubtless dispersed 

 by the agency of the wind, but it appears that in some species 

 synzoic dispersal may also occur {R. glacialis, nivalis and acer). 



IV. The germination is known only in a few species; 

 in some, it takes place during spring, in others during autumn. 

 R. glacialis is remarkable by the fact of its having only one 

 cotyledon. 



V. The roots, in the specimens which have been in- 

 vestigated, fall naturally, according to their anatomy into 

 three groups. 



A. In all the species of Ranunculus and in Batrachium 

 confervoides the primary structure is retained. The epidermis 

 is thin-walled and has a tendency to collapse (except in R. 

 acer)] the exodermis is usually distinct, and the radial walls 

 are undulating; both layers are suberized. In several species 

 the two outermost layers of the cortex are slightly coUenchy- 

 matously thickened; in this respect the species with creeping 

 stems form an exception. Tlie median part of the cortex is 

 more or less broken down, often to a great extent; the degree 

 of disintegration is probably dependent not only upon specific 

 differences but also upon the lesser or greater degree of humi- 

 dity of the locality. Around the usually thin-walled, suberized 

 endodermis some layers of the cortex are always retained. R. 

 acer has a thick-walled endodermis. The central cylinder is 

 usually diarch to tetrach. The pericycle is one-layered; on 

 the outside of each group of sieve-tissue there is more or 

 less distinctly to be seen in all the species a large, pentagonal 

 sieve-tube wedged in between adjacent cells of the pericycle. 



The roots of the second order agree with the above des- 

 cription, only the exodermis is probably not suberized and none 

 of the layers are collenchymatous. 



The following species had endotrophic mycorrhizas, 



