CURRENT LITERATURE 
NOTES FOR STUDENTS 
The “graft hybrids” of Bronvaux.—Since the work of WINKLER in pro- 
ducing so-called “graft hybrids” among several species of Solanum, the older 
chimeras, Laburnum Adami and the “Crataegomespili of Bronvaux” have 
attracted renewed attention. The graft hybrids of Bronvaux originated from 
the callus formed at the junction between a Crataegus monogyna stock and a 
scion of Mespilus germanica. These aberrant branches were of two types 
and have been described under the names Crataegomespilus Asnieresii and 
Crataegomespilus Dardari. The first of these resembles more closely Crataegus 
monogyna, while the Crataegomespilus Dardari has a much closer resemblance 
to Mespilus. A thorough study of these two chimeras has been made by 
MEVER,! in order to find means of identifying the tissues which have been de- 
rived from the two parent species. In most respects the tissues of Crataegus 
and Mespilus are so similar that few distinguishing features can be found. 
Numerous chemical tests failed to discover any method for certainly differ- 
entiating the tissues of the two species. A study of the chromosomes, how- 
ever, gave one good criterion, for, although the number of chromosomes in the 
two species is the same (32 in the diploid nucleus), the chromosomes of Mes- 
pilus germanica are considerably longer and thinner than those of Crataegus 
monogyna. ‘The capacity to produce anthocyan, which is present in the epi- 
dermis of the fruits of Crataegus, is lacking in the fruits of Mespilus, while the 
reverse relation with respect to anthocyan is seen in the fact that Mespilus 
flowers turn reddish in aging, while those of Crataegus remain white. The 
fruits of the two chimeras show no anthocyan, and the flowers of both turn 
reddish with age. 
The only clear distinction that could be found in the internal anatomy of 
the two species was visible only in longitudinal sections. The libriform vessels 
in Mespilus possess spiral thickenings which are absent in those of Crataegus. 
In both chimeras the libriform vessels lack spiral thickenings. The form of 
the epidermal cells is also strikingly different in the two species, those of 
Mespilus germanica being oblong, while those of Crataegus are nearly spherical. 
The cuticle of Crataegus is level, while that of Mespilus follows the contour 
of the rounded ends of the underlying cells. The epidermis of both chimeras 
agrees with that of Mespilus. The fruits of Mespilus are five-loculed and 
those of Crataegus one-loculed. Both of the chimeras have one-loculed fruits. 
EYER, J., Die — von Bronvaux. Zeitschr. Ind. Abstamm. 
Vink 13: Pied 233. 19 
323 
