CALYPTOSPORA 373 
ficidia on leaves of Abies pectinata, A. Nordmanniana, 
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, 
Kiihn, and Bubak. It has been shown that the ecidia can be developed 
in artificial cultures on other species of Abzes (but not on Tsuga canadensis 
or Pseudotsuga Douglasiz), 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 «cidia 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. 59. 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 
(2.c.) 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 This statement was originally made by Hartig, but is 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 Abzes liable to attack, it would be 
well 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 Magnus. 
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 
