OF THE UNITED STATES. 29 



Aecidia hypophyllous, in pulvinate, orange-colored thickenings of the leaves, 

 densely agglomerated, 10-40 together, often arranged in a circle ; peridia yellowish-brown, 

 cylindrical-acute, recurved, generally entire but when old becoming fimbriate; peridial 

 cells large, polygonal, coherent thi-oughout, thick-walled, SSfi-l^^ broad by 58|U-76(U. long ; 

 spores yellowish-brown, sui'face slightly papillose, roundish-angular, 18u-22/x in diameter ; 

 spermogonia numerous in reddish-yellow spots on the surface of the leaves. 



On the leaves of Pyrus americcma, A^nekmchier canadensis, Crataecjus sp. 



Eastport, Maine (Farlow) ; Amherst, Mass. (Frost) ; New York (Peck) ; Ithaca, N. Y. 

 (Dudley). Northern and Central Europe. 



This species in its typical form is common on the leaves of Pyrus americana at East- 

 port. The spots on the leaves are of a brilliant reddish-yellow color, the spermogonia 

 very numerous and the aecidia crowded together in a circle, the swelling of the leaf being 

 in the form of a circular elevation and not at all tubercular as in the preceding species. 

 The peridia are long and recurved and preserve their shape for a considerable time, be- 

 coming at length lacerate. In this, its typical form, it is more robust than R. lacerata, 

 and the peridial cells are broader and thicker. The form which occurs on Amelanchier 

 has fewer aecidia in a cluster, the substance of the leaf around their bases is more dis- 

 tinctly tubercular, and the peridia are shorter and more acute than in the form on the 

 mountain ash, approaching, perhaps, R. lacerata. The occurrence of R. cornuta on 

 species of Crataegus in the United States possibly requires confirmation. I have speci- 

 mens on C. crus-galli which may perhaps be referred to R. cornuta but am not certain. 

 None of the Schweinitzian specimens of Caeoma cylindrites which I have examined seem 

 to belong to the present species, but possibly some of the varieties mentioned under that 

 head in the Syn. Fung. Am. Bor. may be placed here. 



EOESTELIA LACERATA (Sow.) Fr. 



Aecidium oxyacanthae Pers., Syn., 206. 



Aecidiiim Mespili and oxyacanthae D.C., Flore franqaise, Vol. vi, p. 98. 



Aecidium laceratum Sow., British Fungi, PI. 318. Exsicc. Ravenel, Fungi Carol., Fasc. 



V, 96. 

 Aecidium crataegi var. oxyacanthae Schweinitz, Syn. Fung. Car. Sup., No. 4.32. 

 Caeoma cylindrites var. Crataegi punctatae, var. arborescentis and var. C. oxyacanthae 



Schweinitz, Syn. Fung. Am. Bor., No. 2899. 

 RoesteUa lacerata Fr., Summa Veget. Scand., Vol. ii, p. 510 ; Sprague, Contrib. to New 



England Mycol., p. 329 ; Decades of Maine Fungi, p. 180; Peck, 22d and 24th Reports; 



Farlow, Bull. Bussey Inst., Vol. ii, p. 255 ; Tuckerman, Plants of Amherst ; Harkness 



and Moore. 



Aecidia hypophyllous, sometimes on the stems and young fruit, seated on the yellow 

 pulvinate thickening of the leaves, slender, cylindrical or somewhat subulate, recurved, 

 densely clustered, 5-30 together ; peridia yellowish-white, rather delicate, soon splitting 

 and becoming fimbriate, the divisions not extending to the base of peridium ; cells of 

 peridium narrow, 20,11 broad by 55jii-75jU. long ; spores brownish, roundish-oblong, surface 



