86 A Monograph of the Erysiphaceae 



thecia before the appendages had become uncinate (see figure in 

 Journ.de Bot. 2: 217.. / 1888). M. Patouillard kindly sent me 

 specimens (now in the Kew Herbarium), on which was noted, 

 ^\ Erysiphc {Uncinidd) populi Pat.; differe de U. aditnca [ f/. 

 salicis\ par ses theques sub-6-spores.*' Examination showed the. 

 asci to be 4— 6-spored, and in this and all other, characters M. 

 Patouillard's plant agrees perfectly with' U, salicis, 



I/, Cohnnbiajia Selby was published as growing. on, vSr/z/d'/Z^^r/Vr 

 lateriflora at Columbus, Ohio. The^author remarked (324),^ 

 '* This species resembles U, circinata C. & P. in the form of 

 perithecia, but Is distinguished from it by the more abundant niy- 

 eelium, by the broader asci, and the fewer and larger" spores. ■ Un- 

 like previously reported species of the genus its host is a herb and 

 one commonly affected by an Erydphe\ . The^ material on hand is 

 ^nature though rather scanty."^ Professor Selby very kindly sent 

 me the type specimens for examination. ' I found the perithecia to 

 measure 100-150 u. in diameter, the appendages are numerous, 

 hyaline and thin-walled throughout, simply uncinate, I-I^^ times 

 the diameter of the perithecium ; the asci are about 60 x 35 /-«, 

 5- or 6-spored, spores 20-22, x 10 a. In all respects, therefore, 

 the specimen agrees well with U. ,salicis ; U, circiJiata differs in the 

 larger perithecia, shorter appendages, larger asci, and 7—8 spores. 

 Professor Selby's material shows some perfectly ripe perithecia, 

 but is rather scanty, and I have not been able to satisfy myself 

 perfectly that the UncimilawdL^ grooving on the Scutellaria, There 

 is certainly a species of mildew growing on the Scutellaria leaves," 

 as is shown by the presence of some young perithecia on the my- 

 celium, but, as far as I have been able to see, these are too young 

 to show any appendages, and it is just possible that they do not 

 belong to the Uncinula^ but to Erysiphe cichoraccannn^ which is 

 not uncommon in America on this Scutellaria. The Uncinula has 

 not been reported subsequently on Scutellaria^ ^.nd considering 

 that there is a possibility that its presence on this plant was ac- 



i 



cidental, it will be wiser to wait, for confirmation before recording 

 Scutellaria lateriflora as a host plant for Uncinula salicis. Perhaps 



a parallel case to the above is afforded by the occurrence of U, 

 ge7iiculata on Hydrophyllum^ mentioned below or of LL salicis on 

 Artemisia (see above). By a curious mistake Saccardo gives, in 



