546 THE PATHOGENIC ALGAE. 



but several inhabit Hepaticae, chiefly species of Anthoceros, Blasia, 

 Pellia, Aneura, Diplolaena, Sauteria, and Biccia. 



Nostoc lichenoides Vauch.^ is a common endophyte in the 

 mucilage-cavities of Anthoceros laevis. The motile algal filaments 

 sain admission through the stomata or mucilage-fissures on the 

 lower side of the thallus. Only one filament is admitted into 

 each cavity, then the opening is closed by an increased turgescence 

 and growth of the guard-ceUs ; the imprisoned Nostoc multiplies 

 to form a colony. 



Leitgeb states that after infection has successfully taken place, 

 and frequently before the stoma has quite closed, the guard- 



Fio. 323. — Aiuibaena azoiloi. Longitudinal section through the posterior lobe 

 of a floating leaf of Azoila carolini&VAu The cavity is filled with ifo^Coc-filaments 

 and septate hairs. 



1, A septate hair, and a filament of Aiiahacna. (t. Tubeuf del.) 



cells divide and ultimately form a three-layered covering of 

 cells over the intercellular space. Simultaneously all the thallus- 

 cells round the infected cavity undergo radial division and grow 

 into the cavity, first as papillae, then as much-branched and 

 septate tubes of various lengths ; the space left between them 

 becomes meanwhile filled with the Nostoc. In the ease of 

 Anthoceros laevis the tubes form a kind of pseudoparenchyma 



^ Bibliography : Janczewski, Botan. Zeitung, 1872, and Annales d. sci. 

 nalur., Ser. 5, xvi. Milde, Botan. Zeitung, 1851. Leitgeb, Akademied. Wissen- 

 schaften in Wien, 1878; also Unternuchungen iiber Lebermoose, i. Goebel, "Die 

 Musoineen," in Schenk's Handbuch d. Botanik, 1882. 



