juiyis, I9IS Ascochyta Clematidina 335 



2503; also those of A. indusiata Bres. on C. recta in Krieger's Fungi 

 Saxonici No. 11 89. In both, the spots resemble those found on C. 

 paniculata and C. jackmanni. In the former the spores are cylindrical 

 i-septate and hyaline. They measure 8 to 12 by 3.2//, the average 

 dimensions being 9.5 by 3.2/z. The spores of the latter species are 

 hyaline to honey-colored, somewhat constricted, and measure 12 to 22 by 

 6.3//, with an average of 19 by 6[x. 



The writer has repeatedly examined the species of Ascochyta on 

 clematis and found it quite variable. The chief difference is in the spores, 

 though sometimes the pycnidia are more deeply immersed than at other 

 times. Plate LIV, figure i, shows a pycnidium in the leaf tissues of 

 C. panictdaia. The spores vary in length from 6 to 28// and in width 

 from 3 to 6/i, but generally they are about 9 to 13 by 3 to 4/£. Plate LII, 

 figure 3, shows the typical spores. The spores are either i- or 2-celled, 

 rarely 3-celled. Some leaves of C. jackmanni collected in the fall of 191 4 

 showed pycnidia having spores as long as 28// and averaging 18 by 5.7/i. 

 Inoculations with material from cultures obtained by the isolation of 

 single spores showed that this fungus was the same as that usually 

 encountered. The various differences in color shown by the spores dis- 

 appear when the spores are plated out under control conditions. Con- 

 sidering the variability of the fungus found by the writer, any of the 

 descriptions given for the different species of Ascochyta described on 

 clematis would in general apply to it. Hence, the name selected is the 

 oldest one, Ascochyta clematidina Thiimen, the description of which 

 is here emended as follows : 

 Ascochyta clematidina (Thiimen). 



Ascochyta clematidina Thiimen, Pilzfl. Sibir. n. 619, 1884, in Sacc. Syll. Fung., v. 3, p. 396. 



On stems and foliage; spots circular, zonate to indefinite; pycnidia (on leaves 

 mostly epigenous, sometimes hypogenous) tan to dark brown, scattered to gregarious, 

 globose to subovoid, immersed, then erumpent, ostiolate, averaging 120/1 in diameter; 

 spores variable, subellipsoidal to cylindrical, i- or 2-celled, septa more or less medial, 

 sometimes constricted, hyaline to dilute honey or olive color, often guttulate, 6 to 28 

 by 3 to 6.4/i, usually 9 to 13 by 3 to 4/u; exuded spore mass honey-colored, sometimes 

 pink. 



On living leaves and stems of Clematis paniculata, C. virginiana, and the hybrids 

 C. hendersoni, C. henryi, C. jackmanni, C. ramona, C. Duchess of Edinburg, C. Mme. 

 Baron Veillard, and C. Mad. ^douard Andri. According to Von Thiimen, it occurs 

 also on living leaves of C. glauca. As yet no perfect form of A. clematidina has posi- 

 tively been found. 



CONTROL EXPERIMENTS IN 1 91 3 



In 1 91 3 some 2-year-old plants of C. panictdaia that had made a dense, 

 matted growth of tangled vines were badly diseased, while a bed of 

 seedlings next to them was free from disease. In an attempt to save 

 the 2-year-old plants, they were cut back to a length of 4 to 6 inches and 

 then sprayed with Bordeaux mixture on July 21. A small area was left 

 unpruned and unsprayed as a check. By October 17 the seedlings, 



