Gyninosporangiuiu. 233 



are slightly smaller than those of G. clavariccfo7-Jiit\ and the cells of the 

 pseudoperidia are delicately reticulated and longitudinally wrinkled. 

 In thirty-six cultures I have produced the aecidiospores on C. oxyacan- 

 tha from G. confusinn ; in six cultures on Pyriis vulgaris (quince), and 

 in seven on Mespihis gerinanlca (medlar). I have failed to produce 

 any result on apple in three experiments, and on beam in one. Of these 

 cultures several were serial. Thus, on May 16, 1887, three pears 

 and one thorn were infected from the same material ; on the three pears 

 no result was obtained, but on the thorn aecidiospores were produced. 

 In another series, on the same day, a pear, a quince, and a thorn were 

 infected ; the quince and thorn had spermogonia on the 30th, but 

 no result was obtained on the pear. Again, on June 16, a ciuince, 

 two pears, a thorn, a beam, and an apple were infected ; the quince 

 and thorn became infected with the aecidiospores, but the pears, 

 apple, and beam remained free. On April 25, a pear and two thorns 

 were infected ; the two thorns produced the aecidiospores (spermogonia 

 appearing on one on May 5, and on the other on the loth), but the pear 

 remained free. On May 7, 1885, the same infecting material was 

 applied to a medlar and six thorns ; both the medlar and all the 

 thorns became affected by the 20th with the spermogonia. In due 

 time on the thorns the fficidiospores were developed, and these were 

 on June 25 applied to a healthy sabine bush. In September, it was 

 noted that many of the leaves had turned yellow ; these during the 

 winter and following summer (1886), fell off, and in March, 1887, the 

 G. co7tfusnm appeared on those parts of the branches from which the 

 leaves had fallen off. It may be added, that in only one duplicated 

 culture out of the hundred I have made in elucidating the life-history 

 of the sabine Gyinnosporangia have Eecidiospores on both thorn and 

 pear been produced from the same infecting material. This was 

 doubtless caused by an accidental mixture of teleutospores. 



Gymnosporangium clavariaeforme. (Jacq.) 



^cidiospores —Pseudoperidia on yellow, thickened spots, at first 

 flask-shaped, then cylindrical, light brown, at length becoming 

 fimbriate above. Spores subglobose, verrucose, pale brown, 

 20-40 X 20-28/z. 



Teleutospores — Mycelium perennial, causing fusiform swellings on 

 the branches. Spore-masses ligulate, compressed, sometimes 

 bifid, at first firm and cartilaginous, becoming gelatinous, pale 

 orange, about 10 mm. long. Spores fusiform, constricted, 

 dark yellow, 70-120 x 14-20/x. 



