38 



FARLOW ON GYMNOSPORANGIA. 



the earliest appearance of the spermogonia of the different Roesteliae, and of the appear- 

 ance of the sporiferous masses of Gymnosporangia in limited regions. This last point I 

 think has not received sufficient attention from European botanists. Unless I am mis- 

 taken, I have seen the spermogonia of R. lacerata near the Bussey Institution, at a date 

 preceding the maturing of any of the Gymnosporangia of the neighborhood. 



Cornu 1 has called attention to the fact that Roesteliae may be made to appear out of 

 season by means of cultures. Another important fact is to ascertain how many of our 

 Roesteliae are perennial. This, at least, appears to be the case with R. aurantiaca. 

 If it should be shown that several of our Roesteliae are perennial, a fact true with regard 

 to most of our Gymnosporangia, and to grow in regions remote from species of Juniperus 

 and Cupressus, then one could not help feeling that any connection between the two 

 genera was probably accidental rather than genetic. 



EXPLANATION OF PLATES. 

 Plate I. 



Figs. 1-6. Oymnosporangium macropus Lk. 1, Sporiferous masses fully expanded ; 2, the same in a 

 dry condition, showing the knot or cedar-apple, and the contracted sporiferous masses surrounded by the 

 raised collar at the base ; 3 and 4, teleutospores, with a part of their pedicels ; 5 and 6, spores producing 

 promycelia and sporidia, 6 showing a promyceliuni forming at the apex. 1 and 2 natural size, 3-6 mag- 

 nified 350 diameters. 



Figs. 7-11. Oymnosporangium fuscnm var. globosum Farlow. 7, Sporiferous masses expanded ; 8, the 

 same contracted, and showing the knot formed; 10 and 11, spores with pedicels; 9, spore producing promy- 

 celia. 7 and 8 natural size, 9-11 magnified 350 diameters. 



N. B. 9-11 have been drawn on too small a scale, and should be enlarged one fourth in comparing with 

 the spores of other species. 



Plate II. 



Figs. 13-17. Gymnosporangium Ellisii Berk. 13, portion of a distorted branch of Cupressus thuyoides 

 with sporiferous masses expanded; 14-17, spores of the same; 17, spore bearing promycelia; 16, anomalous 

 spore forking at the tip. 13 natural size, 14-17 magnified 350 diameters. 



Figs. 18-21. Gymnosporangium biseptatum Ellis. 18, stem of Cupressus thuyoides, bearing expanded spo- 

 riferous masses ; 19-21, spores of the same ; 20 producing promycelia. 18 natural size, 19-21 magnified 350 

 diameters. 



Figs. 22-27. Gymnosporangium clavipes C. and P. 22, twig of Juniperus virginiana, with sporiferous 

 masses expanded, and distorted, acerose leaves, to be compared with 23 which represents a normal branch ; 

 24, 25, spores with enlarged pedicels ; 26, spore which has fallen from pedicel and produced promycelia at 

 both extremities; 27, spore with terminal and lateral promycelia. 22 and 23 natural size, 24-27 magni- 

 fied 350 diameters. 



iBull. Soc. Bot., 1878. 



