Order USTILAGINALES ' 



By George Perkins Cwnton 



Parasitic fungi infesting various parts of herbaceous flowering plants. In- 

 fection through the vpry young tissues of any part of the host or more fre- 

 quently limited to special portions, often only through the germinating seed. 

 Mycelium local or widespread, consisting of hyaline, somewhat septate, 

 branched filaments practically limited to the interior of the host ; at maturity 

 often disappearing partially or wholly through gelatinization ; fertile mycelium 

 compacting into masses and giving rise, in various ways, to chlamydospores 

 formed from their internal contents ; rarely developing a conidial stage on the 

 exterior of the host. Sori evident, usually forming dusty or agglutinated 

 spore-masses that break out in definite places on the host ; more rarely perma- 

 nently embedded in the tissues. Spores (chlamydospores) light- to dark- 

 colored, 4-35 fJ- in diameter, single, in pairs, or in spore-balls, the latter often 

 composed in part of sterile cells. Germination by means of a promycelium, 

 usually producing terminal or lateral sporidia which may be capable of a 

 saprophytic existence in nature and which often reproduce themselves abun- 

 dantly through a yeast-like process of budding. 



Promycelium usually with lateral sporidia at septa. Fam. 1. Ustil agin ace ae. 



Promycelium with clustered terminal sporidia, Fam. 2. Tilletiaceae. 



^ This paper is based on the writer's monograph of North American Ustilagineae (Proc. 

 Best. Soc. Nat. Hist. 31 : 329-529) published in October, 1904. In the present paper there 

 are omitted the general notes, notes under genera and species, most of the older Euro- 

 pean synonyms, the list of species showing general distribution, and the bibliography. 

 Xhere are added to the paper such further species, hosts, and distributions as have since 

 come to hand. The following are the additional species and varieties described here : 

 Entyloffta Holwayi Sydow, Sphacelotheca diplospora glabra Clinton & Ricker, var. nov., 

 Sphacelotheca diplospora verruculosa Clinton, var. nov., Tilletia Eragrostidis Clinton & 

 Ricker, Tilletia Muhlenbergiae Clinton, sp. nov., Tilletia Redfieldiae Clinton, sp. nov., 

 Tolyposporium globuligerum (Berk. & Br.) Ricker, Urocystis Lithophragmae Garrett, sp. 

 nov., Ustilago Kellermanii Clinton, sp. nov., Ustilago punctata Clinton, sp. nov., Ustilago 

 Rickerii Clinton, sp. nov., Ustilago Sieglingiae Ricker. Ustilago Panici-leucophaei Bref. 

 has been placed under the genus Sphacelotheca. Under each species have also been added 

 references to the type locality (including host) and to illustrations of the species. The 

 names of the hosts have been made to conform in general with the nomenclatture to be 

 used in the Flora. Under each species, however, the writer has indicated in parentheses 

 the former name when there has been a change. Finally there have been added under 

 the genera artificial keys to aid in the identification of the species. 



Volume 7, Part 1, 1906] 1 



