58 



in the propagula occurring in an isolated manner instead of in 

 dense aggregations, Pycnidia Lave been described by the above 

 mentioned French authors for A. Millardetu These are found 

 scattered in the thallus on both ascigerous and conidia-bearing 

 plants, and do not show any structural peculiarity. 



For specific distinctions the form and size of the thallus have 

 to be noted, but more especially the distribution of the propagula 

 and the arrangement of their component cells • The ascospores 

 vary slightly in size, but otherwise they are singularly constant. 



The Dominica Plant. 



On close examination the West Indian specimens were found to 

 be distinct from all species previously described. Though in 

 habit and general appearance they very closely resemble both 

 A. Millardeti and A. Tonduzi, they differ in the form and arrange- 

 ment of the propagula- In the former these bodies are produced 

 in oval or elongated cavities, and are triquetrous with terminal 

 hairs; in the latter the cavities are circular and the propagula are 

 irregular or botryoidal in form. The Dominica plant possesses 



1. Leaf of Citrm Medica with AticTiia dominicana nat. size. 



2. Plant of A. dominicana showing irregular swellings containing 

 asci a, and conidial cavities 6 x 15, 



^ 3. Young propagulum showing the budding off of cells from the 3 

 primary branches x 400. 



4, Mature propagulum x 400. 



6. Section through thallus showing peripheral filaments and an ascus 

 X 400. 



