PODOSPHAERA 29 



■t 



4. Appendages branched in a definite manner at the apex, or if unbranched (J/, as/ra- 

 gali) while, assurgent and fasciculate. Aficrosphacra, 



Appendages simple, or irregularly branched (no definite apical branching), some- 

 times obsolete, usually more or less similar to the mycelium, and interwoven with 

 it, very rarely (^. toftilis) brown, assurgent and fasciculate. JLrysiphe, 



PODOSPHAERA Kunzc, Myk. Heft. 2 : in. 1823 



Perithecia globose, or globose-depressed ; ascus solitary, sub- 

 globose ; spores eight. Appendages equatorial or apical, dark 

 brown or colorless, dichotomously branched at the apex, branches 

 simple and straight, or swollen and knob-shaped ; very rarely {P. 

 laicotricJid) of two kinds, one set apical, brown, rigid, unbranched 

 ■or rarely 1—2 times dichotomous at the apex, the other set basal 

 short, flexuous, simple or vaguely branched, frequently obsolete. 

 Etym. Tzoh^^pcs, and ai^atpa^ spJiacra. — Dlstrib. Europe, Africa, Asia, 

 North America, and probably Australia. — 4 species and i variety. 



The single ascus separates the genus from all others of the Ery- 

 sipliaccac e^ccept Sphacrotheca, from which it is at once distinguished 

 by the definite equatorial or apical appendages. P, laicotricha 

 which has hitherto been placed in the genus SphaerotJicca, and 

 known as S, mali^ is anomalous among the Erysiphcae in possess- 

 ing two kinds of appendages. 



Ke> to ttie Species of Podospliaera 



I. Basal appendages present, apical appendages usually unbranched. 4. leucotricha. 



Basal appendages absent 



2, 



2. Appendages erecto-fasciculate, springing from near the apex of the perithecium. 3. 

 Appendages more or less spreading and equatorially inserted. 4. 



3. Appendages 6-l2j^ times the diameter of the perithecium, colorless, or occasionally 



pale brown towards the base. 2. SchlecJitendalii. 



Appendages 1-8 times the diameter of the perithecium, dark brown for more than 



half their length. I. oxyacanthae var. tridadyla. 



4. Appendages colorless, or faintly tinged with brown at the base, branches of apex not 



swollen. 



3. biuncinata. 



Appendages dark-brown for more than half their length, ultimate branches of the 

 apex knob-shaped. r. oxyacanthae. 



I. PoDOSPiiAERA OXYACANTHAE (DC.) de Bar}'. [Figs. 96, 97, 99- 



108, I If 



Erysiphe oxyacanthae DC, Mem. Soc. d'Agric. Depart. Seine 

 10:235. JS07; DC. Fl. Fr. 6: 106. 1815; Duby, Bot. Gall. 

 2 : mZ. 1830 J Dun et Mont. Fl. d' Alger. (Crypt.) 564, 1846-9; 

 Tul. Sel, Fung. Carp, i : 202, pL 4, f. 10. 1861. 



