1916] HOAR—STERILITY IN RUBUS CYA | 
Recently a specialist in Oenothera (BARTLETT 29) has published 
an article in which he makes what he calls “‘12 elementary species 
of Onagra,” 5 of which are made out of our common evening prim- 
rose (Oneothera biennis). This is surely a perplexing condition. 
BRAINERD (30), who has made a very careful study of the species 
of Viola, both in the field and under controlled conditions, has met 
with a very disconcerting situation. He finds a difference in the 
classes of hybrids. When hybrids are made between nearly related 
but distinct species, they have characters intermediate between 
the unlike characters of the parent forms. They are stable, breed- 
ing true from generation to generation, and showing a very vigorous 
growth, but are always more or less sterile. On the other hand, 
when crosses are made between species which are more or less 
doubtfully distinct, or between races, or between a species and a 
variety, there is usually quite a different result. In the first place, 
the offspring of such crosses have not intermediate characters, but 
recombinations of the unlike characters of the parent forms. Asa 
result, the individual plants are dissimilar, some reverting to one 
or the other parent form, and others presenting the “‘sporting” 
characteristics. Another very important characteristic difference 
is that we do not usually find the fertility damaged either in the 
first or in subsequent generations. He speaks of these as “‘the so- 
called Mendelian hybrids, the despair of the systematist but the 
vantage ground of the breeder of new and useful ‘varieties.’”’ 
Finally, he cites the instance of several species of A quilegia which he 
allowed to grow indiscriminately together, and which in a short time 
gave off 5 hybrids. This case is similar to that of the violets which, 
Owing to the greater amount of the cleared land, can be greatly 
increased in range and hence have a much greater opportunity for 
hybridization. 
In connection with BRAINERD’s remark concerning his so-called 
Mendelian hybrids it seems well to quote a few lines from another. 
CorRRENS (31) was one of the first to rediscover MENDEL. He 
evidently from the first appreciated certain limits to the scope of 
MENDEL’s laws. 
Inzwischen hat mir ein Aufenthalt in den Alpen Gelegenheit gegeben, 
eine Anzahl von Bastarden zwischen unzweifelhaften Arten zu untersuchen 
