Vol. 39 No, 2 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
ee ee 
FEBRUARY tg12 
Variation in the floral structures of Vitis* 
M. J. Dorsey 
(WITH PLATES I-3) 
The genus Vitis has invited special attention botanically and 
horticulturally on account of its economic importance. The 
normal morphology of the flower is, of course, well known, and 
some observations have been made respecting variation in the 
different floral members. It would seem, however, that there is 
accessible no sufficient account of variation in the floral types. 
In the present paper the writer proposes to bring together some 
general facts and observations and especially to record some 
studies on the structural and numerical variation in the floral 
parts of certain species and varieties. 
GENERAL FLORAL HABITS OF VITIS 
The flower of Vitis presents a number of interesting variations, 
occurring both in the number and in the development of floral 
parts. In the flowers of many other genera where there is a 
multiplication of floral envelopes, there is often a complete or 
partial metamorphosis of some of the members into others, as 
in doubling, where stamens may be found showing a more or less 
complete transformation into petals. In Vitis, however, there 
occur either only completely developed floral members, or if there 
are modifications, they are in the direction of the suppression of 
certain members. There is, moreover, a close numerical relation 
* June 1911. Laboratory of Plant Physiology, Cornell University, Contri- 
bution No. 4. 
[The BULLETIN for January 1912 (39: 1-36) was issued 10 F 1912.] 
37 
