1914] 



FROMME—AECIDIUM CUP 



15 



condition is illustrated in text fig. 3. The general direction of the 



hyphae on the lower border of the figure is tangential to the curved 



basal surface of the mass. These horizontal hyphae are present in 



all forms, and, as previously stated, give rise to the perpendicular 



hyphae. Fusions between cells of these 



horizontal hyphae are sometimes found in 



Ur. Caladii, but the gametes of this species 



are normally borne in the perpendicular 



hyphae. In P. Eatoniae, however, the 



gametes seem to be normally formed in 



these horizontal hyphae. P. Hydrocotyles 



is more like P. Claytoniata in the position 



of the gametes (text fig. 4) . About 5 or 6 



cells are found in the perpendicular hyphae 



below the pseudoparenchyma, and appar- 



ently any of the cells in this tissue may 



function as gametes. 



Sexual fusions and spore-production 



The fertilization in all these forms is 



accom 



gametes that are norm 



t> 



in size and position. The first fusions are 

 found in the central part of the gametic 

 tissue, and the wave of fusions proceeds 

 from this center toward the lateral borders 

 of the aecidium. The fusions are quite ^^m^^^^P. 



abundant, and, though not SO readily dis- Hydrocotyles: a, apical sur- 



FiG. 4. — Section through 



man^ 



face; fc, basal surface; g, 

 gametic tissue; p, pseudo- 

 parenchyma. 



be found in a favorable section (fig. 2$). 



The process of fusion is identical with that 



found in the caeomas, and involves the dissolution of an area of 



the adjoining cell walls between two gametes. The gametes before 



the fusions are more or less differentiable bv their size, the size of 



asm. The nucleoles are 



especially large and conspicuous. 



the 



