Hedgcock, Hunt, Hahn: Coleosporium 187 



of Adelia ligustrina under a tree of Pinus glabra heavily infected 

 with Peridermium minutum. Healthy plants of Adelia ligustrina 

 secured from another locality were packed in direct contact with 

 fresh aecia of this Peridermium, mailed to Washington, D. C, 

 and placed in pots. The uredinia of the Coleosporium appeared 

 on these plants in about two weeks after they were potted, and 

 later telia. On March 28, 1919, inoculations were made again in 

 the greenhouse at Washington, D. C, on eight healthy plants of 

 Adelia ligustrina with the aeciospores of the Peridermium col- 

 lected on Pinus glabra at Gainesville, Fla., February 28, 1919. 

 Uredinia of the Coleosporium appeared on the leaves of three 

 plants April 14, and telia about June 1 ; six control plants re- 

 mained free from the rust. This proves that i't is the alternate 

 stage of Peridermium minutum (10). This species of Coleo- 

 sporium with minute sori differs from other known species of this 

 genus, and is now given the name Coleosporium minutum Hedge, 

 and Hunt, comb, nov., with the following description: 



Uredinia hypophyllous, numerous, small, scattered on slightly 

 chlorotic areas on the leaves, circular to elliptic, 0.1-0.5 mm. in 

 diameter, averaging 0.25 mm., orange-chrome, fading with age 

 to white, ruptured epidermis inconspicuous ; urediniospores 

 sphaeroid to obovoid or ellipsoid, 15-23 by 18-31 fx, averaging 

 18.7 by 24.5 /jl, walls irregularly thickened at the apex, 2-8 /x thick, 

 averaging 4.9 jx verrucose with coarse conical tubercles, 2-4 /x in 

 diameter, averaging 2.6-3.8 /x. 



Telia hypophyllous, small, scattered or somewhat gregarious, 

 rarely confluent, circular to elliptic in outline, 0.16-0.36 by 0.18- 

 0.36 mm., averaging 0.22 by 0.26 mm., grenadine red, darkening 

 with age ; teliospores with wall swelling 20-36 /x above, averaging 

 24.2 fx ; contents orange-chrome, fading to almost colorless, cylin- 

 dric to clavate or oblong, 18-32 by 30-70 /x, averaging 23.1 by 

 44.9^, rounded or obtuse at the apex, obtuse to narrowed below. 



Coleosporium minutum Hedge, and Hunt has been collected in 

 the United States only and as follows: 

 O and I. On Pinus: 



P. glabra, Florida, in 1916, Gainesville, March 14 (20737), 

 March 15 (20768, type of Peridermium minutum), March 20 

 (20801) ; in 1918, March 13 (25126), March 28 (25223), May 6 

 (29118) in 1919, February 24 (32103) and March 12 (32230). 



