ORDER USTILAGINALES (tHE SMUTs) 



413 



phase. This is the common case. But if one chromosome pair undergoes 

 disjunction in the first nuclear division and the other chromosome pair 

 waits until the second division before undergoing disjunction the result 

 will be four nuclei with four different combinations of the sexual factors, 

 i.e., four sexual phases in the same promycelium. This doubtless occurs in 

 the other smut species also. The sexuality of smuts has been studied also 

 by Paravicini (1917), Bauch (1922 and later publications), Dickinson 

 (1927, 1928), Kniep (1926), Sleumer (1932), and others. Liro (1924) de- 

 scribed a peculiar method of sexual reproduction in Ustilago vuijckii Oud. 

 & Beijer., on Luzula multiflora (Hoffm.) Lej. This should be reinvestigated 



Fig. 139. Subclass Teliosporeae, Order Ustilaginales, 

 Family Ustilaginaceae. Germination of teliospores by two 

 or more promycelia. (A) Sphacelotheca columellifera (Tul.) 

 Yen. (B) Sphacelotheca schweinfurthiana (Thiim.) Sacc. 

 (C) Sorosporium consanguineum E. & E. (After Yen: 

 Rev. mycol, 2(2):76-84.) 



and similar studies undertaken on other species for it is very different 

 from the method usually accepted for this family. The sporogenous hy- 

 phae in the ovaries of the host are slender and more or less dichotomously 

 branched. The cells are binucleate. From the base toward the apex of 

 these hyphae the cells swell successively, usually leaving a slender portion 

 containing the septum between each cell and the one next above it. At the 

 upper part of a cell a branch is produced, containing one nucleus. This 

 branch is separated from the cell below by a septum. It pierces the cell 

 above by a very fine tube and the cytoplasm and nucleus pass into it, 

 making it 3-nucleate. In the meantime a similar process from this cell 

 takes one of the two original nuclei and transfers it to the next overlying 

 cell, and so on. Then the two nuclei unite and a thick wall is formed, 

 within and free from the original wall. Sometimes an "antherid," as Liro 

 calls these small branches, from another hypha fertilizes a cell and in that 



