1921-22 DEPARTMENT OF LANDS AND FORESTS 257 



If search at any point failed to reveal the presence of currants or goose- 

 berries, it was extended, many times for hours, until it was certain that these 

 plants did not occur. The location was then given a station number, the usual 

 notes taken and "no ribes" recorded. 



Frequently in the eastern end of the territory the blister rust was found 

 on currants. These cases were recorded and their locations and other details 

 are presented elsewhere in this report. In each case the occurrence of the rust 

 was given some attention and neighbouring pine trees were examined, but no 

 pretence is made of having given this aspect of the problem exhaustive treat- 

 ment. 



Results. 



1. Species occurrence. — -The following species occur: 



Ribes glandulosum (skunk currant), 

 " triste (swamp red currant), 

 " lacustre (swamp black currant), 

 " hudsonianum (Hudson Bay currant), 

 " americanum (wild black currant), 

 Grossularia cynosha'i (prickly gooseberry), 



" oxyacanthoides (smooth gooseberry), 



" hirtella 



" rotundifolia 



2. Siiscept bility. — It is significant that all the species occurring in this 

 territory are among the most susceptible to attack by the rust. According 

 to an analysis by Spaulding (U. S. D. A. Bulletin 957) of inoculation experiments 

 with these plants both in the greenhouse and out of doors, all except the Hudson 

 Bay currant fall easy victims to the rust. There are no data on the susceptibility 

 of this latter species. Though there is but little to choose between the others, 

 the wild black currant is apparently the most susceptible, and the various 

 species may be arranged in the following order on the basis of their susceptibilty : 



1. Wild black currant, 6. Prickly gooseberry, 



2. Swamp red currant, 7. Skunk currant, 



3. Swamp black currant, 8. Smooth gooseberry, 



4. Grossularia hirtella, 9. Hudson Bay currant. 



5. Grossularia rotundifolia. 



3. Distribution. — Of the five species of currants, the skunk currant is 

 overwhelmingly preponderant. All of them except the wild black currant are 

 swamp forms. Nevertheless the skunk currant exhibits a remarkable versatility 

 and was found in every type of locality, dry and moist, except under virgin 

 white pine (on the Opeogo River) and in sphagnum bogs. The ground cover in 

 a virgin pine forest is usually almost entirely wanting and in sphagnum bogs is 

 composed exclusively of a very definite flora consisting of the moss, certain 

 Ericaceae, pitcher plants, orchids, etc., so that the absence of the skunk currant 

 here is not noteworthy. Four extensive bogs were examineed to see if it could 

 be found in this habitat, and though the plants occur around the edges in mucky 

 soil or even in the clefts of rocks among ferns, they were never seen in the bog 

 proper. It is hardly an exaggeration to say that in this territory the skunk 

 currant is universally distributed. 



All the other species of currants are of secondary importance from the point 

 of view of distribution. In only three cases were other currants found growing 



17 L.F". 



