196 Rhodora [OCTOBER 
I [he] cannot think it probable that the species [ A. Zeesz] is a variety 
of A. idaeus."' The theory that the plant is a hybrid was further 
maintained by William Culverwell, a distinguished authority on hy- 
bridization as well as upon the genus Rubus. Mr. Culverwell pub- 
lished a figure of a plant, perhaps identical with the round-leaved 2. 
Leesii, which he states was produced by crossing the strawberry and 
raspberry. One of the main points in the argument for the hybrid 
origin of the plant was found in the general sterility of its drupes, a 
condition which, as we shall see, is otherwise satisfactorily explained 
by Dr. Focke of Bremen. 
Among the numerous discussions of the round-leaved raspberry, 
one in particular is of interest to us. In 1873, Professor Areschoug 
published a paper entitled, “ On Rubus Idaeus, L.; Its Affinities and 
Origin."3 In brief, Professor Areschoug's argument was as follows : 
In Europe Auus idaeus is a unique species, the other fruticose Rubi 
of Europe belonging to the blackberry type, and presenting such 
a variety of intergrading forms that their specific limitations are very 
obscure. ubus idaeus, however, differs from all these species in 
having red or amber berries which separate readily from the recep- 
tacle, in having thin bark which scales off from the old canes, and in 
producing from the root buds which develop into canes. "These and 
many minor points distinguish Rubus idaeus from the other European 
species. Yet this isolated European raspberry varies excessively, a 
tendency charactetistic of genera with many closely related species, 
but not ordinarily seen in plants isolated from other species of the 
genus or subgenus. Ordinarily, then, species which have a strong 
tendency to vary are more or less completely connected with each 
other — for instance, our American blackberries, or asters. “ But 
KK. idaeus, L., though greatly variable, produces no intermediate 
forms connecting it with the other European species, and this circum- 
stance seems to me [Areschoug] to be of such importance that I 
consider it as belonging to another type." 
From the study of material from different regions, Areschoug 
came to the conclusion that it is “very likely that Æ. zZaeus, L., as 
wellas the North American forms most closely related to it, have 
* Syme, Eng. Bot. iii. 162. 
* For detailed discussion see Gard. Chron. n. s. xx (1883) 12, 276, 342. 
3Journ. Bot. xi (1873), 108-115 [translated and revised from Botaniska 
Notiser, 1872, 168-181]. 
