THE AMERICAN BOTANIST 71 



PkIvORIa IX V101.ETS — Everybody knows that in normal 

 violet flowers, the lower petal is spurred. When peloric flow- 

 ers occur this "irregular" flower may be made "regular" bv 

 each petal producing a spur. A writer in Torrcya records a 

 plant of Viola primulaefolia with flowers of this nature, which 

 was found on the bank of a stream at West Raleigh, North 

 Carolina, in 1912. This plant was removed to a more suit- 

 able location for study and has since formed a considerable 

 colony all of which bear peloric flowers. Seeds from the ori- 

 ginal plant produced new plants with the characteristics of the 

 parent, thus giving additicmal evidence that such plants may 

 breed true and that a race of peloric plants may thus be es- 

 tablished. A curious feature of the abnormal flowers is that 

 they are mostly 4-parted instead of having five parts in a 

 whorl as orthodox violets do. Many of the flowers, however, 

 failed of complete peloria and there was noticed a considerable 

 irregularity in the number of parts in a whorl. 



The Arctic Tundra. — The polar margin of North 

 American vegetation is characterized, as in other continents, 

 by the treeless tundra. In Alaska the tundra occupies a nar- 

 row strip along the Bering Sea, and on the northern coast it 

 covers the polar slopes of the northernmost branch of the 

 Rocky Mountains. From the Mackenzie river eastward, its 

 soutliern limit strikes inland across the lake region to reach 

 Hudson Bay at Fort Churchill. The specific feature of the 

 American tundra as compared with those of Siberia and Green- 

 land is the wealth and extent of its lichen carpets. Though 

 the ling heath is entirely absent from America, other species 

 of the heather family are numerous, and in the tundra or bar- 

 rens their dwarf bushes are preponderating. Among them 

 occur evergreen Rhododendron, Kalmia, Ledum, bearberry 

 and other bushes of a similar character, clad with lichens. 



