2 BrierlEY, Life-History of LeptospJucria LemaiiecB. 



Overton (12) in 1906 and Stone (16) in 191 2 have 

 quoted Woronin in their pubh'cations. 



The principal features of my investigation of Leptos- 

 pJiceria LcDianecr, were completed before I had seen 

 Woronin's account, and with slight additions confirm his 

 results. 



Host Plant. 



Leinanea is an exclusively freshwater genus belonging 

 to the group Nemalionales of the Rhodoplyces, and grows 

 in tufts attached to submerged rocks in flowing water. 



The structure of the sexual shoots, important to an 

 understanding of the morphology of the fungus, is well 

 known (Sirodot (15), Atkinson (l)\ but may be sum- 

 marised here. The thallus is cylindrical and hollow, and 

 from apex to base runs an axial row of tubular cells, the 

 " Zentralfaden." At more or less regular intervals this is 

 connected by a whorl of four ray cells to longitudinally 

 running generative filaments closely applied to the inner 

 surface of the thallus. Arising from these filaments, and 

 penetrating through the cortex to the periphery, are the 

 procarpia. Each of these, after fertilisation, gives rise to 

 ooblastema filaments, from which are budded off carpo- 

 spores, which radiate into or almost fill the lumen. 



The tissue is somewhat cartilaginous and composed 

 of three zones of cells — a peripheral layer of small, very 

 closely set prismatic cells, containing chromatophores ; 

 a middle layer of larger polyhedral cells ; a medullary 

 layer of large rounded cells. Mucilage fills the inter- 

 cellular spaces, surrounds the shoot, and thickly lines or 

 fills the lumen. At more or less regular intervals on the 

 surface of the thallus, and bearing relation to the ray 

 cells, are the antheridial whorls, (See Text-fig. 4 for a 

 transverse section of the Lcmmiea shoot.) 



