722 ADDITIONAL EXERCISES 



tt Appendages more or less spirally coiled at the apex. 6 Uncimila. 

 ** Appendages united at the base into a plate. 7 PhyllacHnia. 

 2. Perithecia without appendages, sessile or mycelium. 8 Erysibella. 

 (b) Spores divided. 9 Saccardia. 



Key to the Species of Sph^rotheca (After Salmon) 



Brief Characterization. — Perithecia subglobose, ascus solitary, eight-spored. 

 Appendages floccose, brown or colorless, spreading horizontally and often interwoven 

 with the mycelium, simple or vaguely branched, frequently obsolete. 



1. Mycelium persistent, thick, pannose, forming dense patches of special hyphae 

 in which the perithecia are more or less immersed. (2) 



Mycelium without these characters. (4) 



2. Persistent mycelium usually satiny and shining, white, sometimes becoming 

 gray, or pale brown. 2 pannosa. 



Persistent mycelium dark brown. (3) 



3. Inner wall of perithecium separating from the outer, hyphse of persistent 

 mycelium very tortuous. 4 lanestris. 



Inner wall not separating, hyphas straighter. 3 mors-iivm. 



4. Perithecia 60 to ySju in diameter, ascus 60 to 75 by 42 to 50^1, inner wall of 

 perithecium separating from the outer. 5 phytoptophila. 



Perithecia 50 to 120M in diameter, ascus 45 to 90 by 50 to 72/*; inner wall 

 scarcely separating. (5) 



5. Cells of outer wall of perithecium 10 to 20M wide, averaging 15/x. i hutmili. 

 Cells 20 to 30 (rarely 40) /x wide, averaging 25/^. i humuli var. fuUgnea. 



Key to Species of Podosph^ra (After Salmon) 



Brief Characterization. — Perithecia globose, or globose-depressed; ascus solitary, 

 subglobose; spores eight. Appendages equatorial or apical, branches simple and 

 straight, or swollen and knob-shaped; very rarely of two kinds: one set apical, 

 brown, rigid, unbranched or rarely one to two times dichotomous at the apex; the 

 other set basal, short, flexuous, simple, or vaguely branched, frequently obsolete. 



1. Basal appendages present, apical appendages usually unbranched. 4 

 leiicotricha. 



Basal appendages absent. (2) 



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

 thecium. (3) 



Appendages more or less spreading and equatorially inserted. (4) 



3. Appendages six to twelve and one-half times the diameter of the perithecium, 

 colorless, or occasionally pale brown toward the base. 2. Schlectendalii. 

 Appendages one to eight times the diameter of the perithecium, dark brown 

 for more than half their length, i oxyacantha var. tridactyla. 



4. Appendages colorless, or faintly tinged with brown at the base, branches of 

 apex not swollen. 3 biuncinata. 



