338 THE FUNGI WHICH CAUSE PLANT DISEASE 



scattered, or at first somewhat gregarious and crowded, 0.3-0.5 mm. 

 across, soon naked, yellow or orange-yellow, ruptured epidermis 

 inconspicuous; spores elUpsoid or globoid, 17-22 by 20-30 fi; 

 wall rather thin, 1-2 /i, closely and strongly verrucose; contents 

 orange-yellow when fresh, fading to colorless. 



III. Telia hypophyllous, scattered irregularly or sometimes 

 crowded and confluent, slightly elevated, 0.3-0.5 mm. across, 

 reddish-orange; spores with wall swelling 30-40 /i thick above; 

 contents orange-yellow fading to colorless, terete, 15-23 x 55- 

 80 /x, rounded or obtuse at both ends; basidiospores globoid or 

 elliptical, about 12 x 18 /i, orange-yellow. 

 I. .^cia on Pinus rigida. 



II and III. Uredinia and telia on Aster, Solidago and culti- 

 vated aster (Callistephenis) ; widespread and common. The con- 

 nection between the stages was demonstrated by inoculations by 

 Clinton.i9«' "' 

 C. senecionis (Schum.) Fries. 



0. Pycnia amphigenous, scattered, numerous, originating be- 

 tween mesophyll and cortical layer, noticeable, 0.2-0.3 mm. wide, 

 0.5-1 mm. long, dehiscent by a longitudinal 

 slit, 70-100 fi high. 



I (=Peridermium oblongisporium). .^cia 

 from a limited mycelium, amphigenous, bul- 

 late, tongue-shaped, 1-2 mm. long, 0.7- 

 1 mm. high, whitish; peridium rupturing ir- 

 regularly, fragile, white, cells overlapping, outer 

 and inner walls of same thickness, 3-4 n, outer 

 smooth, iimer moderately verrucose; spores 

 FiQ. 251.— Coieospo- broadly ellipsoid, 17-24 by 28-36 /*, wall 

 ?howfn|gi™"na: coloriess, thick, 3-4 ja, densely verrucose with 

 tion of teliospores. prominent elongate papillae. 

 After Plowright. tt tt J- • u v, ii xu- i i xx j 



11. Uredinia hypophyllous, thickly scattered, 



about 0.5 mm. across; early naked, bright orange-yellow fading 

 to pale-yellow, ruptured epidermis evident; spores elliptical- 

 globoid or obovate-globoid, 17-21 by 20-27 n; wall thin, 1- 

 1.5 II, evenly but not densely verrucose, with low papillse. 



III. Telia hypc^hyllous, scattered, often confluent, small, 0.3 

 mm. across, briUiant orange-yellow fading to pale orange-yellow; 



