260 NORTH AMERICAN FLORA [Volume 7 



I. Aecia chiefly hypophyllous, from an unlimited mycelium, usually occupying all of 

 the under surface of the affected leaves, evenly and often densely scattered, short, cupu- 

 late, 0.3-0.4 mm. in diameter ; peridium somewhat recurved, finely lacerate ; peridial cells 

 rhomboidal, somewhat overlapping, 13-19// broad by 18-25^ long, the outer wall rather 

 thick, 4-7 /x, transversely striate, smooth, the inner wall thinner, about 3ju, somewhat 

 striate, finely verrucose : aeciospores globoid or broadly ellipsoid, 12-16 by 15-19/1 ; wall 

 pale-yellow or colorless, thin, l/i, finely and densely verrucose. 



II. Uredinia amphigenous, scattered or sometimes in annular or crowded groups, 

 roundish, 0.4-1 mm. across, earlynaked, pulvinate, pulverulent, cinnamon-brown, ruptured 

 epidermis not conspicuous ; urediniospores globoid or broadly ellipsoid, 15-20 by 19-23 /t; 

 wall pale golden-brown, rather thin, about 1.5-2/i, moderately and sparsely echinulate, the 

 pores 3-6, scattered. 



III. Telia amphigenous, scattered or sometimes in annular groups, roundish, 0.4-1 

 mm. across, earlynaked, pulvinate, somewhat pulverulent, dark chocolate-brown, ruptured 

 epidermis not conspicuous; teliospores broadly ellipsoid or obovoid, 15-18 by 18-26 /t, 

 usually rounded at both ends; wall cinnamon -brown, rather thin, 1.5/i, with a lighter- 

 colored, flattish or conical papilla over the germ-pore, moderately verrucose with papillae 

 scattered or sometimes arranged in more or less evident longitudinal rows ; pedicel hyaline, 

 short, deciduous. 



A cosmopolitan and somewhat variable species, which has been shown by cultures to possess 

 strongly marked races, treated by some authors as species. These races, so far as known, are four 

 and correspond to the host genera as follows: a, Poinseiiia, b, Dichrophyllum, c, the smaller- 

 leaved and more prostrate species of Chamaesyce, and d, the larger-leaved and more upright 

 species of Chamaesyce. 

 On Euphorbiaceae : 



Adenopetahtm. gramineiim (Jacq.) Arth. {Euphorbia gr amine a Jacq.), Hidalgo. 

 Chamaesyce adenoptera (Bertol. ) Small {Etiphorbia adenoptera Bertol. ) , Guatemala, 



Nicaragua. 

 Chamaesyce albomarginata (T. & G.) Small {Euphorbia albomargi^iata T. & G.), 



California. 

 Chamaesyce arizonica (Engelm.) Arth. {Euphorbia arizonica Engelm.), Arizona. 

 Cham-aesyce brasiliensis (Lam.) Small {Euphorbia brasiliensis Lam.), Guatemala. 

 Chamaesyce Fendleri (T. & G.) Small {Euphorbia Fendlerl T. & G.), Arizona, Utah. 

 Chamaesyce Geyeri (Engelm.) Small {Euphorbia Geyeri Engelm.), Illinois, Mississippi, 



Nebraska. 

 Chamaesyce glyptosperma (Engelm.) Small {Euphorbia\glyptosperma Engelm.), Colorado, 



Iowa, Minnesota, Nebraska, North Dakota, Oregon, South Dakota. 

 Chamaesyce hirsuta (Torr.) Arth. {Euphorbia hirsuia Wiegand), New York. 

 Chamaesyce hirta (L.) Millsp. {Euphorbia hiria L- , E.pilulifera 1,.), Florida; Jamaica; 



Porto Rico. 

 Chavtaesyce humislrata (Engelm. ) Small {Euphorbia hum.istrata Engelm . ) , Illinois, 



Indiana, Iowa, Missouri, Nebraska, Ohio. 

 Chamaesyce hypericifolia (L.) Millsp. {Euphorbia hypericifolia L.), District of Columbia, 



Florida, Indiana, Iowa, Missouri, Nebraska, New York, North Carolina, Ohio, Penn- 

 sylvania, West Virginia ; Bahamas. 

 Cham-aesyce hyssopifolia (L.) Small {Euphorbia hyssopifolia L.), Florida. 

 Chamaesyce lasiocarpa (Klotzsch) Arth. {Euphorbia lasiocarpa Klotzsch), Guatemala. 

 Cham,aesyce m-aculata (L- ) Small {Euphorbia maculaia L.), Connecticut, Delaware, 



Florida, Indiana, Iowa, Kansas, Massachusetts, Minnesota, Nebraska, New Jersey, 



South Carolina, Texas, Wisconsin. 

 Chamaesyce lata (Engelm.) Small {Euphorbia lata Engelm.), Kansas, Texas. 

 Chamaesyce Nuttallii (Engelm.) Small {Euphorbia Nuttallii Engelm.), Kansas. 

 Chamaesyce peialoidea (Engelm.) Small (^w/Acrifc _^^/a/ozrffa Engelm.), Nebraska, 



South Dakota, Texas. 

 Chamaesyce pilosula (Engelm.) Arth. {Euphorbia pilosula 'Hngelija.), Oaxaca. 

 Chamaesyce polygontfolia (L.) Small {Euphorbia poly gonifolia L.), Illinois. 

 Cham,aesyce Freslii (Guss.) Arth. {Euphorbia Preslii Guss.), Arkansas, Delaware, Illinois, 



Indiana, Iowa, Kansas, Minnesota, Mississippi, Missouri, Nebraska, New Jersey, New 



York, North Carolina, Ohio, Pennsylvania, Texas. 

 Chamaesyce potosina (Fernald) Arth. {Euphorbia potosina Fernald), Hidalgo. 

 Chatnaesyceprostrata (Ait.) Small {Euphorbia prosirata Ait.), Mississippi ; Mexico (state) ; 



Bahamas ; Jamaica ; St. Croix. 

 Chamaesyce serpens (H.B.K.) Small {Euphorbia serpens H.B.K.), Kansas, Louisiana, 



Nebraska ; Mexico (state) ; Jamaica. 

 Chamaesyce serpyllifolia (Pers.) Small (C erecta Lunell, Euphorbia serpyllifolia Pers.), 



Arizona, California, Colorado, Iowa, Montana, Nevada, New Mexico, North Dakota, 



South Dakota, Texas, Utah, Washington ; British Columbia. 

 Chamaesyce T'rtrQ'i Small, Mississippi. 

 Dichrophyllum bicolor (Engelm. & Gray) Kl. & Garcke {Euphorbia bicolor Engelm. & 



Gray), Texas. 



