304 SALMON : SUPPLEMENTARY 
ceum matrice arctissme adpressum canescens, ex hyphis densissime 
intertextis tenuibus (3-4 / crass.) ramulosis septulatis hyalinis 
efformatum : perithecia pauca sparsa amphigena globoso-depressa 
(100-150 p diam.) atro laevia astoma, hyphis basalibus paucis 
radiantibus radicata, tenui-membranacea, contextu minute paren- 
chymatico e ferrugineo ochraceo; asci pauci ovati v. obovatl 
(50-60 » long. x 25~35 4 diam.) brevissime stipitati aparaphysatl, 
2—4-spermi; sporae subcylindraceae (40 y long. x 12 # crass.) 
utrimque obtusissimae e latere (praecipue in parte media) com- 
pressae, laeves, hyalinae, tenuiter tunicatae, nubiloso-farctae.” 
In the specimen sent to me by Professor Spegazzini I was unable 
to find more than one or two quite immature (yellowish) perithecia. 
The subpersistent mycelium is of the same appearance and con- 
sistency as that commonly found in examples of £. polygont (¢. 8 
in specimens on Geranium, Anemone, Polygonum erectum, Peuceda- 
num Oreoselinum, etc.), and there are no characters given in the 
diagnosis quoted above, except that of the length of the spores, to 
separate “ £. deserticola’’ from this cosmopolitan species. 
Although “ Erysiphe euphorbiae Peck” (= Microsphaera euphor- 
biae Berk. & Curt.) has been twice recorded from Belgium—by 
Bommer and Rousseau, Bull. Soc. Roy. Bot. Belg. 25: 169. 1886, 
and Lambotte, Fl. myc. Belg. Supp. 1: go. 1887—it is very im- 
probable that the fungus found really belonged to this North 
American species. The examples recorded by Bommer and Rous- 
seau occurred on Euphorbia amygdaloides. In specimens (now . 
the Kew herbarium) sent by Mme. Bommer, from “ Poix (Bel- 
gique), Sept. 1885,” on which the record mentioned above ve 
based, no perithecia are to be found. Dr, Lambotte informs m© 
that no specimens exist of the example recorded by him. i” 
description given in Fl. myc. Belg. (/. c.), it may be noted, 1s 4 
repetition of Peck’s original diagnosis (Reg. Rep. 26: 80. 1874) 
and has therefore probably not been drawn up from characters 
shown by a Belgian plant. It is quite possible that the “f 
euphorbiae” of Belgium is Sphacrotheca euphorbiae (Cast.): es 
binov ('76) records “ Erysiphe (?) euphorbiae Peck,” on Euphor ad 
virgata, from Russia; I have seen no specimens of this, 
Microsphaera diffusa Cooke & Peck has been recorded by Ser 
binov (76) on Lathyrus pratensis L. from St. Petersburg, Re 
M. diffusa is a North American (United States) species, and 
