174 NORTH AMERICAN FLORA [V01.UME 7 



On Rosaceae : 



Ivesia Baileyi S. Wats., Oregon. 



Jvesia Gordonii (Hook.) T. & G., Utah. 



Ivesia seiosa (S. Wats.) Rydb. (/. Baileyi seiosa S. Wats.), Nevada. 

 Type locality : Glencoe, Nevada, on "-Ivesia Baileyi,'*^ now determined as /. seiosa. 

 Distribution : Central plateau of the Rocky mountains. 



15. Phragmidium Ivesiae Sydow, Ann. Myc, 1 : 329. 1903. 



Uredo Acaenae HUis & Ev. N. Am. Fungi ^756*, hyponym. 1894. 

 Phragmidium affine Sydow, Ann. Myc. 2: 29. 1904. 



0. Pycnia not seen. 



1. Aecia hypophyllous, scattered, roundish or oval, 0.4-1 mm. across, becoming slightly 

 pulverulent, bright orange-yellow fading to pale-yellow, ruptured epidermis not notice- 

 able ; parapliyses wanting ; aeciospores broadly ellipsoid or globoid, 18-20 by 20-26 fi ; wall 

 pale-yellow, rather thin, 1.5-2 ^u, finely and very sparsely echinulate-verrucose with well 

 separated papillae, the pores indistinct, scattered, about 4 or more. 



II. Uredinia hypophyllous, numerous, scattered, round, 0.7-1 mm. across, soon naked, 

 yellowish, ruptured epidermis not conspicuous ; paraphyses very few, small, clavate, thin- 

 walled, colorless, encircling the sorus, often entirely wanting ; urediniospores broadly 

 ellipsoid or subglobose, 16-22 by 19-26 (i ; wall pale-yellow, moderately thin, 1.5-2 /U, rather 

 finely and sparingly verrucose-echinulate, the pores not distinct, scattered, 4 or more. 



III. Telia hypophyllous, at first arising from the uredinia, numerous, scattered, roundish 

 or often irregular, 0.4-1.5 mm. across, soon naked, blackish-brown, ruptured epidermis 

 inconspicuous ; paraphyses none ; teliospores short-cylindrical, 19-26 by 35-51 ^, usually 

 rounded at both apex and base, usually 3- (sometimes 2- or 4-) celled ; wall cliocolate-brown, 

 2.5-3.5 u- thick, smooth throughout or more often minutely verrucose on the upper part 

 about the apex ; pedicel colorless except close to the spore, 5-9 ^ in diameter, usually 

 short, occasionally as long as spore, slightly attenuate below. 



On Rosaceae : 



Acaena tridactyla Presl {^A. trifida Torr. notR. & P.), California. 



Ivesia sericoleuca Rydb., California. 



Poteniilla Bakeri Rydb., Colorado. 



Potentilla Blaschkeana Turcz., California, Montana. 



Poteniilla diversifolia Lehm., Alberta. 



Potentilla Elmeri Rydb., California. 



Potentilla fastigiaia Nutt., Colorado. 



Potentilla filipes Rydb. {P. gracilis Port. & Coult., P. pulcherrima Rydb.), Colorado, Ne- 

 vada, Utah, Wyoming. 



Potentilla fiabelliformis Lehm., Idaho, Washington. 



Potentilla glaucophylla I^ehm., Colorado. 



Poteniilla glomeraia A. Nels., Montana, Oregon. 



Potentilla grosse-serrata Rydb., California. 



Potentilla Hallit Rydb., California. 



Potentilla Hippiana I^ehm., Assiniboia. 



Potentilla monspeliensis I^., Colorado. 



Potentilla Nuttallit Lehm., Colorado, Montana, Wyoming; Alberta. 



Potentilla paradoxa Nutt., Iowa, Nebraska, South Dakota. 



Potentilla pulcherrima I^ehm., Utah. 



Potentilla rubripes Rydb., Montana. 



Potentilla viridescens Rydb., Montana, Utah. 

 Type locality : California, on '■^Ivesia unguiculata,^^ now considered to be /• sericoleuca. 

 Distribution : Mountainous regions from central California and Colorado northward, and 

 occasionally on the plains from Nebraska and western Iowa northward into Canada. 



ExsiCCATi: Clements, Crypt. Form. Colo. 584; Sydow, Ured. 1787, 1947 ; D. Griff. W. Am. 

 Fungi 51, 51a, 51b, 281; Garrett, Fungi Utah. 100, 151; Ellis, N. Am. Fungi 1066 ; Ellis & Ev. N. 

 Am. Fungi 2881, 3150 ; Ellis & Ev. Fungi Columb. 561, 759, 1946 ; Vesterg. Micr. Rar. Sel. 952. 



16. Phragmidium Potentillae (Pers.) P. Karst. Bidr. Finl. Nat. 



'Folk 31 : 49. 1879. 



Puccinia Potentillae Pers. Syn. Fung. 229. 1801. 



Uredo Potentillae Schum. Enum. PI. Saell. 2 : 228. 1803. 



Aregma obtusaia Fries, Obs. Myc. 1 : 225, in part. 1815. 



Phragmidium obtusum Schmidt & Kunze, Deuts. Schwamme 5 : 5. 1816. 



Caeoma Potentillae Schlecht. Fl. Berol. 2 : 121. 1824. 



O. Pycnia amphigenous, few, gregarious and often confluent, in small groups usually 

 surrounded by the aecia, inconspicuous, subcuticular, extending somewhat into the lateral 

 walls of the epidermal cells, pale-yellow, discoidal, low, 100-160 [i in diameter by 25-40 /^ 



high. 



