Paut 3, 1912] ABCIDIACBAB 217 



by a broad, pale umbo, 6-10 m, often appearing vertically striate, the pore of the lower cell 

 next to the septum, usually with the wall much thickened ; pedicel colorless, delicate, 

 fragile, short. 



On Carduaceae : 



Baccharis oaxacana Greenm., Oaxaca. 

 Type locality : Mt. Oaxaca, Mexico, on Baccharis oaxacana. 

 Distribution : Known only from the type locality. 



28. ARGOMYCES Arthur, gen. nov. 



Argomyces replaces Argotelium as described in Result. Sci. Congr. Bot. Vienne 343 (1906) , and 

 used in the key on page 130 ; the change is necessitated by an error in the citation of the type species. 



Cycle of development includes pycnia, uredinia, and telia ; autoecious. All sori sub- 

 epidermal. 



Pycnia globoid or flask-shaped, with ostiolar filaments. 



Uredinia erumpent, definite, usually without paraphyses. Urediniospores borne singly 

 on pedicels, globoid or ellipsoid ; wall yellowish-brown, concolorous, echinulate. 



Telia usually definite, without paraphyses. Teliospores two-celled, usually germinating 

 in situ upon maturity ; wall pale or colorless, and generally smooth. 



Type species, Argomyces parilis Arth. (on Hyptis pectinata). 



Host belonging to family Lamiaceae. 1. A. parilis. 



Host belonging to family Oxalidaceae. 2. A.Oxahdis. 

 Host belonging to family Carduaceae. 



Teliospore-wall uniformly thick. 3. A. Vemoniae. 



Teliosp ore -wall thicker above. 4. A. Baccharidis-multiflorae. 



1. Argomyces parilis Arthur, sp, nov. 



O. Pycnia epiphyllous, few in small groups on discolored spots 1 or 2 mm. across, incon- 

 spicuous, globoid, 130-160 M in diameter. 



II. Uredinia hypophyllous, scattered, round, 0.1-0.4 mm. across, early naked, very 

 pulverulent, chestnut-brown, ruptured epidermis inconspicuous ; urediniospores globoid, 

 or less often broadly ellipsoid, 19-24 by 20-30 Mj usually 20-23 ^ in diameter ; wall dark 

 cinnamon-brown, concolorous, moderately thick, 1.5-3 M) strongly and evenly echinulate. 

 with points about 2 ^ apart, the pores 2 or 3 near the hilum, not very distinct. 



III. Telia hypophyllous, scattered, abundant, round, small, 0.1-0.3 mm. across, early 

 naked, pulvinate, white, ruptured epidermis inconspicuous ; teliospores oblong or lance- 

 oblong, 16-20 by 35-50 /i, narrowed or obtuse at both ends, slightly constricted at the 

 septum ; wall smooth, nearly or quite colorless, uniformly thin, about 1 ,« ; pedicel colorless, 

 terete, delicate, one half to once length of spore. 



On IvAmiaceae : 



Mesosphaerum pectinaiuin (Poir.) Kuntze {Hyptis pectinata Poir.), Jalisco, Morelos, 

 Oaxaca. 

 Type collected at Oaxaca, Mexico, on Hyptis pectinata, November 15, 1903, B. W. D. Holway 



5419. 



Distribution : Central and southern Mexico. 



2. Argomyces (?) Oxalidis (I^ev.) Arthur. 



Uredo Oxalidis Iv^v. Ann. Sci. Nat. II. 16 : 240. 1841. 



Uredo Oxalidearum Cooke, Grevillea 10: 123. 1882. 



Puccinia Oxalidis Dietel & RUis ; Dietel, Hedwigia 34 : 291. 1895. 



Dicaeoma Oxalidis Kuntze, Rev. Gen. 3^ : 469. 1898. 



O. Pycnia unknown. 



II. Uredinia hypophyllous, in orbicular or irregular groups, 2-5 mm, across, often cov- 

 ering the whole surface, round, 0.3 mm. across or less, somewhat confluent, soon naked, 

 pale yellowish- white, at first waxy, becoming pulverulent, ruptured epidermis rather incon- 

 spicuous ; urediniospores globoid, or elliptical-globoid, 16-19 by 17-24 /x ; wall very pale- 

 yellow, very thin 0.8-1 m, minutely echinulate, the pores uncertain. 



III. Telia hypophyllous, in orbicular or irregular groups 2-5 mm. across, often cover- 

 ing the whole surface, round, 0.3 mm. across or less, somewhat confluent, soon naked, very 

 pale brownish -yellow, waxy, ruptured epidermis inconspicuous ; teliospores ellipsoid or 



