THE RUSTS ON FRITILLARIA 369 
The morphological differences of these three species are very 
clearly defined, and the species are easily separated, as shown in the 
analytical key which follows. Because of its close host relationship, 
Uromyces Holwayi Lagerh.^ is included in the key. A description of 
this species, however, is omitted because of the fact that its life- 
cycle, which includes uredinia, precludes any possibility of its being 
confused with the species under discussion. No species of Uromyces, 
other than this one, has yet been reported on Lilium in North America. 
Key to Species on Lilium and Fritillaria 
Telia exclusively considered 
Teliospore-wall moderately thick (2-3 ^u), chestnut-brown. 
Teliospores globoid (exclusive of apiculus), 23-27 by 
31-35 ^t I. Uromyces aecidiiformis. 
Teliospores ellipsoid, 18-25 by 29-39 M 2. Uromyces Holwayi. 
Teliospore-wall moderately thin (1.5-2 fj.), cinnamon- 
brown. 
Teliospores narrowly ellipsoid, 14-23 by 24-35 n, in- 
conspicuously verrucosa in lines 3. Uromyces Miurae. 
Teliospores ellipsoid to broadly so, 23-31 by 31-42 fx, 
delicately rugose 4. Uromyces Fritillariae. 
I. Uromyces aecidiiformis (Strauss) comb. nov. 
Uredo aecidiiformis Strauss, Ann. Wett. Ges. 2: 94. 181 1. 
Caeoma Lilii Link in WiUd. Sp. PL 62; 8. 1825. 
Caeoma aecidiiformis Schlecht. Linnaea i: 239. 1826. 
Aecidium Meleagris Duby, Bot. Gall. 2: 904. 1830. 
Erysihe variolosa Wallr. Fl. Crypt. Germ. 195. 1833. 
Erysibe rostellata var. Lilii Wallr. Fl. Crypt. Germ. 210. 1833. 
Uromyces Liliacearum Unger, Einfl. Bodens 216. 1836. 
Aecidium Liliacearum Unger, Einfl. Bodens 220. 1836. 
Uredo Lilii Rab. Deutschl. Krypt. Fl. i: 12. 1844. 
Uromyces Rabenhorstii Kunze, Rab. Fungi Eur. i6pja. 1873. 
Urom^yces Lilii Kunze, Rab. Fungi Eur. i6gjb. 1873. 
0. Pycnia amphigenous, rather numerous, among the aecia, small, 
0.1-0.2 mm. across, punctate, conspicuous, subepidermal, honey- 
yellow, becoming darker later, chestnut-brown-colored ring encircling 
base, globoid in cross section, 160-190 juhigh by 160-190 fxin diameter. 
1. Aecia amphigenous, for the most part hypophyllous, also 
3 N. Amer. Fl. 7: 242. 1907. (As Nigredo Lilii (G. W, Clinton) Arth.) 
4 
