1900] Fernald, — Rubus idaeus in America 197 
their origin from species which primitively grew in Japan and adja- 
cent countries." The relations of the European raspberry are undoubt- 
edly with Asiatic and American species, and its closest ally is our 
common raspberry, Rubus strigosus, a species so closely related to 
R. idaeus that the two have sometimes been treated as one. A. idaeus 
is spread over Europe and western Asia and Æ. strigosus, common in 
North America, grows in Mandschuria and Japan and through Asia 
to the Altai; so that Æ. zdaeus might have been derived from the 
American A. strigosus. Other evidence, however, shows that a large 
part of the flora of North America originated in eastern Asia,‘ and it 
is more probable that the European and the American plants had 
a common ancestor there, the plant with glandless calyx (2. idaeus) 
spreading westward into northern Europe; the other with glandular 
calyx (A. strigosus) crossing Behring Straits to the American conti- 
nent. 
Now the simple form is considered a more primitive stage in leaf- 
development than is the compound form, so that in Rubus idaeus, 
var. anomalus, we have a plant in which the leaves are much simpler 
in their development than are those of typical Æ. zZaews and the 
nearly identical A. strigosus. After critical study, then, Areschoug, 
Focke, Babington, and others have concluded that the extremely local 
round-leaved raspberry of northern Europe is an unusual form of 
R. idaeus, tending, as shown by its short, round leaves, to revert to a 
simpler ancestral type, and that the plant cannot well be considered 
a distinct species. This conclusion is well supported by the investiga- 
tions of Dr. Focke, who says: *I found that the restraining process, 
by which the form of the foliage leaves was so curiously modified, 
extended also to the carpellary leaves, and that the axes of these was 
[were] shortened, so that they did not close and completely envelop 
the ovules. Of the two ovules in each carpel, one uniformly pined 
away at a very early stage; the other developed itself during the 
blooming time in the normal way, but only few carpels were produced. 
In most cases, however, they dried up whilst the flowering was in pro- 
gress; and, though some appeared to be fertilized, yet seed entirely 
failed to ripen. The infertility of the plant I saw, was correlative to 
the character of its foliage; and we mustlook upon it as only a 
curious form of A. zZaeus, which deviates from the type, so far as the 
! See Asa Gray, Mem. Am. Acad., n. s. vi.;and extract, “The Flora of 
Japan," in Scientific Papers of Asa Gray, ii, 125. 
