Arthur and Kern : Peridermium 437 



subcylindrical, o. 1-0.15 mm. wide, 0.3-1 mm. long, by 0.3- 

 0.5 mm. high ; peridium light reddish-orange fading to white, 

 rupturing along the apical line, peridial cells rhomboidal in longi- 

 tudinal section, 25-30// long, somewhat overlapping, inner wall 

 finely verrucose, transversely striate, 2-3 ft thick, outer of equal 

 thickness, smooth; aeciospores globoid or broadly ellipsoid, 12- 

 18 by 1 6-2 5 fi, wall colorless, rather thin, J -1.5 /a closely and 

 evenly verrucose, except a small area on one side which is smooth 

 and slightly thinner. 



On Larix decidna Mill, in Europe, not yet detected in America. 

 It has been shown by Klebahn and others to be the aecial stage 

 of Melampsoridium betulininn (Tul.) Kleb. The uredinial and 

 telial stages occur on Betida ; they have been collected in many 



localities in this country, both east and west, and the Periderm htm y 

 which is quite inconspicuous, will doubtless be found also. 



30. Peridermium Ephedrae Cooke, Indian Forester 3: 95. 



1877 



Peridirmium Pint minor B. & C. Grevillea 3 : 59. 1874. 

 Coleosporium Senecionis minus De Toni ; Sacc. Syll. Fung. 7: 752. 



1888. 

 Aecidhnn Ephedrae Dietel, in Engler & Prantl, Pflanzenfam. i 1 ** : 

 79. 1897. 



0. Pycnia caulicolous, numerous, conspicuous, subcuticular, 

 scattered irregularly over large areas, honey-yellow becoming 

 golden-brown, conical, or often with broad flat top, 75-130 /i broad, 



50-70 fi high. 



1. Aecia from a perennial mycelium, caulicolous, numerous, 

 scattered over the slightly hypertrophied shoots, cylindrical, slen- 

 der, 0.3-0.4 mm. in diameter, 1.5-2.5 mm. high, dehiscent at 

 apex ; peridium colorless, firm, cells slightly or not overlapping, 

 walls rather thin, outer smooth, inner somewhat thicker and finely 

 verrucose; aeciospores broadly ellipsoid or globoid, 16-20 by 

 19-26 fi ; wall colorless, thin, 1-1,5 p, closely and finely verrucose. 



' On Ephedra nevadensis S. Wats. (E. antisyphilitica S. Wats.), 



Arizona, no date, H. H. Rusby. 



On Ephedra pednncidata Engelm. (as on li E. antisyphilitica"), 



Texas, no date, Ckas. Wright (In Ravenel, F. Car. Exsicc. 3: pj 9 

 part of type collection) ; Bradshaw Mountains, Arizona, June 20 f 



1892, /. IV. Tourney (as on " E. oxycarpa' 9 ); San Luis Potosi, 



