ENDOPHYLLUM 321 



mella of tetraspores up to 2 mm. long, teleutospores oblong, 

 truncate, 12 /A broad. 



Prillieux, Malad. des Plantes Agric., i, p. 271. 



Cronartium flaccidum (Winter) forms its uredospores and 

 teleutospores on the under surface of the leaves of cultivated 

 paeonies. The infected leaves present the appearance of 

 being thickly studded with long hairs on the under surface. 

 Aecidial stage unknown. 



Uredospores variable in form, pale orange, aculeate. 

 Teleutospores forming a cylindric-oblong, often curved or 

 tortuous column, pale brown, 2 mm. high, teleutospores 

 oblong or cylindrical, ends obtuse, brown, 8-12 p diam. 



Cronartium Comptoniae (Peck), of which the first stage is 

 said to be Peridermium pyriforme (Peck), is described as an 

 injurious parasite in the United States by Clinton. The 

 Peridermium attacks the Scots fir and pitch pine. The rust 

 occurs only on the stem, and usually near the base, and as 

 the mycelium is perennial, it appears each year, eventually 

 causing the trunk to swell, and injuring the bark and young 

 wood, thereby stunting or even killing young plants. The 

 Cronartium grows on the sweet fern (Myrica asplenifolia, L.). 



Clinton, G. P., Rep. Conn. Agric. Expt. Sta. (1907). 



ENDOPHYLLUM (LEV.) 



Teleutospores i-celled, produced in chains in a peridium, 

 and resembling aecidiospores in Puccinia^ but germinating by 

 the formation of a promycelium bearing secondary-spores as 

 in Puccinia. 



Houseleek rust (Endophyllum sempervivi. Alb. and Schw.) 

 is not uncommon as a parasite on the common houseleek 

 and on other species of sempervivum. The peridia are 

 embedded in the tissues of the leaves at first, then expand 

 and become broadly cup-shaped with a whitish edge. In- 

 fected leaves are longer, narrower, and paler in colour than 

 normal ones. The mycelium is perennial in the host- 

 plant. 



Spermogonia appear first, then the teleutospore condition, 

 the teleutospores being produced in peridia like aecidia- 

 spores. Teleutospores subglobose, orange, warted, i -celled, 

 20-30 p. diam. 



X 



