Part 3, 1912] ABCIDIACEAK 241 



f 



38. Nigredo aemula Arthur. 



Uromyces aemulus Arth. Bull. Torrey Club 38 : 373. 1911. 



0. Pycnia very few, punctiform. 



1. Aecia ampbigenous, rather closely but irregularly arranged in oval groups 0.5-1 cm. 

 long, on pale untbickened spots, cylindrical, 0.2-0.3 mm. in 'diameter, 0.3-0.6 mm. higb ; 

 peridium colorless, tbe margin erose or somewhat lacerate ; peridial cells rhomboidal, 13-19 

 by 19-26 M, the outer wall thick, 5-7 /x, transversely striate, the inner wall thinner, 3^/i, 

 strongly verrucose ; aeciospores globoid or irregularly ellipsoid, 20-24 by 23-26 m, often 

 angular ; wall pale yellow, moderately thick, 1.5-2ju, finely verrucose. 



II. XJredinia ampbigenous, widely scattered, rather prominent, oblong or oval, 0.2-0.4 

 mm. broad by 0.5-2 mm. long, blister-like, dehiscent by a longitudinal slit, yellowish or 

 light cinnamon -brown, somewhat pulverulent, ruptured epidermis conspicuous ; uredini- 

 ospores globoid or broadly ellipsoid, 22-29 by 25-33 /x ; wall golden-yellow, moderately 

 thick, 1.5-2 ju, inconspicuously echinulate, the pores 5-8, scattered, indistinct. 



III. Telia ampbigenous, prominent, widely and rather evenly scattered, elliptical to 

 elongate -oblong, 0.3-1 mm. broad by 0.8-3 mm. long, at first covered by the gray epidermis, 

 eventually naked, somewhat pulverulent, dark chocolate-brown or blackish ; stroma absent ; 

 teliospores globoid or obovate-globoid, 18-24 by 24-30 ju ; wall chestnut-brown, concolorous, 

 moderately thick, 2-2.5 /x, slightly or not thickened above, 2.5-4 fj,, smooth ; pedicel slender, 

 slightly tinted, about once length of spore, usually persistent. 



On Alliaceae : 



Alluim acuminatum Hook., Utah. 



Allium, brevistylum. S. Wats., Colorado, Wyoming, 



Allium validum. S. Wats., Nevada. 

 Type locality: Yancey's, Yellowstone National Park, Wyoming, on Allium, brevistylum. 

 Distribution : Central Rocky Mountain region, mostly at higher altitudes. 

 KxsiCCATi : Garrett, Fungi Utah. 83 (in part) ; D. Griff. W. Am. Fungi J92. 



39. Nigredo bicolor (Ellis) Arth. Result. Sci. Congr. Bot. 



Vienne 343. 1906. 



Uromyces bicolor 'BXMs] Coville, Contr. U. S. Nat. Herb. 4 : 231. 1893. 

 Urom-yces aierrimus Dietel & Holway ; Dietel, Erythea 3 : 78. 1895. 

 Uromyces bicolor BHis & Ev. Bull. Torrey Club 24 : 282. 1897. 

 Caeomurus bicolor Kuntze, Rev. Gen. 3^ : 449. 1898. 



0. Pycnia ampbigenous, scattered among the aecia, often at tips of the leaves, puncti- 

 form, honey-yellow, inconspicuous, depressed-globoid, 80-100 ju wide by 60-80 /a high. 



1. Aecia ampbigenous, loosely and irregularly arranged in oval groups 0,5-1 cm. long, 

 often at tips of the leaves, on pale untbickened spots, urceolate, 0.2-0.4 mm. in diameter ; 

 peridium colorless, the margin irregularly lacerate, rather fragile ; peridial cells rhomboidal, 

 16-19 by 23-29 M, the outer wall thick, 5-7 m, inconspicuously and transversely striate, the 

 inner wall thinner, 3-4 ju, strongly verrucose ; aeciospores broadly ellipsoid, 21-26 by 25-35 m, 

 often angular ; wall yellow, moderately thick, 1.5-2 m, finely verrucose. 



II. Uredinia ampbigenous, somewhat gregarious and inclined to be restricted to small 

 areas surrounded by telia, usually large, prominent, oval, 0.2-0.6 mm. broadby 0.5-3.5 mm. 

 long, blister-like, dehiscent by a longitudinal slit, yellowish or light cinnamon-brown, some- 

 what pulverulent, ruptured epidermis conspicuous ; urediniospores broadly ellipsoid or 

 obovoid, 24-29 by 28-34 M ; wall golden-yellow, moderately thick, 1.5-2 ^i, inconspicuously 

 echinulate, the pores 7-12, scattered, distinct. 



III. Telia ampbigenous, very small, punctiform, but more usually confluent into den-. 

 dritic groups, or into compact compound sori 1-5 mm. long, permanently covered, chocolate- 

 brown to grayish-black, each small sorus surrounded by a strongly developed, golden-brown 

 stroma; teliospores broadly obovoid or pyriform, 19-26 by 26-37 m, usually angular, obtuse 

 or rounded above, obtuse or narrowed below ; wall chestnut-brown, concolorous, moder- 

 ately thick, 1.5-2 /x, only slightly thickened at apex, 3-5m, smooth; pedicel slender, slightly 

 tinted, one half to once length of spore, usually deciduous. 



On Alliaceae : 



Allium, acuminatum Hook., Colorado. 



Allium canadense I,., Massachusetts, Missouri, Texas. 



