CALYPTOSPORA 373 



^Ecidia on leaves of Abies pectinata, A. Nonlnxmniana, 

 June — September ; teleutospores on stems of Vaccinium Vitis- 

 idaea, July — September. England, Wales, Scotland. Very 

 rare. (Fig. 278.) 



The life-history has been experimentally demonstrated by Hartig, 

 Kulm, and Bubak. It has been shown that the iccidia can be developed 

 in artificial cultures on other species of A hies (but not on Tsuga canadensis 

 or Pseudotsuga l><>uglasii), though it is not recorded on any of these in 

 natural conditions. Saccardo's citation of "Abies canadensis" in the 

 Sylloge is probably an error. The teleutospores are recorded also on 

 several other species of Vaccinium, including V. Myrtillus A. Gray, in the 

 United States, but the secidia have not been observed there. 



The infested branches of the Cowberry stand perfectly erect ; the 

 plant becomes taller and the leaves stunted. No uredo-stage occurs. 

 For the life-history see p. o9. The mycelium is perennial in the Cow- 

 berry, producing fresh crops of teleutospores year after year ; this may be 

 the origin of the (presumably) erroneous statement in the Kew Bulletin 

 (I.e.) that the basidiospores are able to infect the Vaccinium again, as well 

 as the Silver Fir. This statement was originally made by Hartig, but is 

 unsupported by any experimental evidence. 



When planting any of the species of Abies liable to attack, it would be 

 w«U to look for and burn all infested bushes of Cowberry in the neighbour- 

 hood ; they are easily recognisable by their peculiar habit. The fungus 

 cannot attack the Firs unless the infested Cowberry is near enough to 

 convey the infection. 



Distribution : Europe, North America. 



HYALOPSORA Mac 



mis. 



Teleutospores in one or two layers, produced in the 

 epidermal cells which are united into crusts; spores with 

 colourless membrane, each divided by vertical septa into 2 — 4 

 (or more) cells. Uredo-sori subepidermal, without a peridium 

 or with a very rudimentary one, but surrounded by paraphyses; 

 uredospores of two kinds, yellow, sessile, furnished with evident 

 germ-pores. On Ferns. 



It has been suggested that the species of Hyalopsora are 

 hetercecious, Abies and Pinus being named by Bubak (1906) as 



