Perisporiacese, Erysiphese, Ezysiphe. 15 



Hab. in foliis Plataui occidentalis, YoDkers, Amer. bor. 



24. MicrosphaBra Symphoricarpi Howe (cit. in Peck. 1. c). 



Hab. iu foliis Sy mphoricarpi racemosee, Yonkers, Ame- 

 rica bor. 



25. Microsphaera Menispermi Howe (cit. in Peck. 1. c). 



Hab, in foliis Menispermi canadensis, Youkers, Amer. bor. 

 2G. Microsphaera densissima (Schw.) Peck. 2l Rep. New-York. Ery- 

 siphe clensissima Schw. Syn. Am. Bor. n. 2479. — Hypmisma 

 densissimum tomentum filamentosum himantioideum, filis robustis, 

 eleganter orbiculatim effiguratum sistit; a semi-uncia ad duas 

 uncias efifusum; fihs candido-lacteis intertextis in ambitu subra- 

 diantibus; peritheciis globosis, nigro-fuscis, crebris. 



Hab. in foliis Quercus, Bethlehem (Schw.), Saratoga, Amer. 

 bor. (Peck.) — Distinctissima species, raaculas definite orbiculares, 

 compactas, albas formans, Peck. 1. c. 



ERYSIPHE Hedw., Lev. in Ann. Scienc. nat. 1851, t. XV, p. 161. 

 (Etjm. Evysibe, rubigo). — Perithecia superficialia, sphteroidea 

 vel hemisphserica, undique clausa, primitus lutescentia, dein fu- 

 sca, tandem atra, minuta s. minutissima, ceraceo-membranacea, 

 mycelio arachnoideo, ssepe contexto, fugaci vel persistente irapo- 

 sita appendicibusque flocosis, simplicibus vel vage ramosis num- 

 quam dichotomis cum mycelio intertextis suff^ulta. Asci plures in 

 quovis perithecio. ovoidei vel subovoidei, brevissime pedicellati. 

 Paraphyses nullae. Sporidia ovoidea, hyalina. Conidia ovato-oblon- 

 ga Oidii erysiphoidis formas spectantia. 



Clavis specierum. 



Linkii 



taurica ( coinmunis 



lamprocarpa Asci 4-8-spori . 1 giganlasca 



Galeopsidis \ Mariii 



Burioei \ clensa 



Montagnei i graminis 



tortilis V vernaiis 



horridula Asci 8-spori . < Ulmarice 



IJmbelliferarum j fuscata 



Euphorbice ^ Erodii 



spadicea \sci 8-12-spori lanuginosa 



Rubi : Tuckeri : epixylon : epigcea : densa : Vaccinii 

 Chelones : Liriodendri : Phlogis : quercina : Asterum 

 Syringce : Viburni : Quisquiliarum : Verbemv : Am- 

 brosice : Ccanothi : Gerardice : 2\ecator. 



56 



57 



58 



Asci 2-spori . . 

 Asci 2-3-spori . 

 Asci 3-4-spori . 



Species dubije 

 V. minus notse 



