22 



MORPHOLOGICAL DEVELOPMENT. 



visible without the microscope. But, in some cases, these 

 vegetal aggregates of the first order grow to appreciable 



sizes. In the mycelium of some fungi, we have single cells 

 developed into long branched filaments, or ramified tubules, 

 that are of considerable lengths. An analogous structure char- 

 acterizes certain tribes of Algce, of which C odium adherens, 

 Fig. 4, may serve as an example. In Botrydium, another 

 alga, Fig. 5, we have a structure which is described as simu- 

 lating a higher plant, with root, stem, bud, and fruit, all 

 produced by the branching of a single cell. And among 



fungi the genus Mucor, Fig. 6, furnishes an example of 

 allied kind.* Here, though the size attained is much greater 

 than that of many organisms which are morphologically 

 compound, we are compelled to consider the morphological 

 composition as simple; since the whole can no more be 

 separated into minor wholes, than can the branched vascular 



* In further illustration, Mr. Tansley names the fact that in the genus 

 Caulerpa we have extremely complicated forms often of considerable size 

 produced in the same way. The various species simulate very perfectly the 

 members of different groups among the higher plants, such as Horse-tails, 

 Mosses, Cactuses, Conifers and the like. 



