LIFE FORMS 



53 



the range of life forms in plantlike animals has some resemblance in 

 such land plants as fungi, lichens, liverworts, and even higher plants. 

 However, their segregation into communities so as to give a physiog- 

 nomic aspect, comparable to those of major plant communities, is 

 doubtful except in the case of coral banks. The phenomenon is also 

 essentially limited to warm seas. The significance and usability of 

 these forms in community study are, in any event, much less than 

 among land plants. 



Several genera of corals (Wood-Jones, 1910) develop a tall straight 

 form in deep still water, a much-branched one in moving water, and 



Figs. 6-11. — Showing the parallelism in growth form of a sessile plant and a 

 sessile animal. 6-8, Forms of Pinus montana (after Schroter, 1908): 6, from 

 protected vallej-s; 7, from mountain sides; 8, from mountain moors. 9-11, Forms 

 of Madrepora: 9, from deep water; 10, from barrier pools; 11, from rough water. 

 The differences are due to injury to the leader or dominant growing point. 

 (After Wood-Jones, 1910.) 



amorphous lumps in rough water (Figs. 9-11). These are somewhat 

 parallel to the forms of certain conifers in still valleys, windy moun- 

 tainsides, and timber line (Schroter, 1908). The former is a response 

 to waves and currents, the latter to wind and snow, but both are the 

 result of the injury to a single dominant bud or zooid. The rather 

 striking parallel is shown in Figs. 6-11. 



The commercial bath sponge shows several forms: a sphere when 

 suspended on a wire, a spheroid when growing on an elevation above 

 the bottom, and a palmate irregular form when surrounded by plants 



