i82 Sorosporium. 



Sori very prominent, blackish-brown, appearing in the tassels and ears 

 and forming compact masses, which may include the entire in- 

 florescence, at first enclosed in a pinkish to whitish membrane 

 which soon ruptures, and the spores are dispersed, leaving the ray- 

 like remains of the columella. 



Membrane consisting of the outer tissues of the host-plant and 

 sterile cells derived from the fungus, which form several layers of 

 clear, more or less rounded cells, arranged in sub-spherical groups, 

 and which may also occur mixed up with the spores. 



Spore-balls dark-brown, globose to oval or irregular, firm at first, 

 but afterwards readily separating, 80-112 yi in length. 



Spores globose to subglobose, or sometimes slightly ellipsoid to 

 ovoid, somewhat opaque, minutely but densely verruculose, 

 10-13 /( diam. 



On Zea Mays L.— Maize. 



Victoria — Orbost, April., 1901 (Pescott) and April, 1906. Lindenow, 



Feb.-May, 1908. Near Orbost, May, 1909. 

 New South Wales— Richmond, 1891. Singleton, May, 1899 (Wad- 

 dell). 



This species was at first recorded as Ustilago niaydis Corda = U. zeae 

 (Beckm.) Ung. by Dr. Cobb in New South Wales, hut further investigation 

 soon showed that it was not the ordinary Maize Smut of America. It is 

 distinguished from that species by neither enlarging the ears nor forming 

 larg3 smut boils, by generally confining itself to the inflorescence and not 

 attacking the leaves, and by the larger and more minutely verruculose spores. 

 In addition, the spores are in balls at first and not solitary. It is fairly 

 common in some of the later crops in maize-growing districts. In a specimen 

 of U. zeae from Sydow's Ust. Exsicc. 157 on Maize from America, the spores 

 were coarsely echinulate and 8-11 /.i diam. 



In the ovaries the membrane may envelop only spores mixed up with 

 clusters of the sterile cells, or in other parts of the plant there may be a 

 central core of plant tissues that have not been destroyed. The mycelium 

 enters the grain from the base and gradually replaces the tissue of the ovary. 

 At the base of the ovary you may still find some of the plant cells which have 

 not yet been completely disintegrated, and at the top the membrane may be 

 entirely composed of fungus cells. It is a case of gradual absorption of the 

 plant tissues by the fungus. The systematic position of this smut has re- 

 ceived considerable attention in America. Kuehn first named it U. rei- 

 liana in 1875, then Clinton called it Cintractia reiliana, and finally in 1902 

 SpTiacelotheca reiliana. Norton^ retained it as U. reiliana, although he observed 

 that "the spores are aggregated in masses, and this species seems much like 

 a Sorosporium, but until further studies of the development I have left it 

 here." In a very young smut cob the spores are seen to be in clusters as 

 shown in Plate XXX., so that its final resting-place is as a Sorosporium. 

 ' I Germination. — This has already been described. The spore germinates 

 readily in water in 21 hours, and forms both lateral and terminal conidia. 

 In nutritive solutions there is a luxuriant development of conidia which 

 sprout in a yeast-like manner and form colonies. 



(Plates XII., XIII., XXX.) 



