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THE VASCULAR CONNECTIONS AND THE
STRUCTURE OF THE TENDRILS IN
SOME CUCURBITACEAE
By Kali Das Sawhney, M.Sc.
Professor of Biology, Islamia College, Peshawar.
During 1917 and 1918 the writer investigated the anatomy of a number of cultivated species belonging to the Cucurbitaceae. A few writers have already dealt with the subject, and special mention must be made of Tondera (4) who has carefully investigated the vascular connections of a number of species of this family, and Muller (3) who has worked out the anatomy of the tendrils. The writer has re-examined some of the species worked out by these writers. Their results have been confirmed in a general way. Since however these two papers are not easily available to the ordinary reader and many species investigated by the writer have not been investigated by these writers and in view especially of some interesting results obtained, it is proposed to give a brief summary of the results arrived at by the writer.
It is well-known that the vascular bundles in the stems of the Cucurbitacese are generally arranged in two rings of five bundles each. The bundles are usually known as bicollateral as they possess phloem towards the inside of the xylem in addition to the external phloem. The bundles of the inner ring are as a whole larger than the outer bundles. These facts should be borne in mind in the following description unless otherwise stated.
Another point to be remembered is the position of the various organs at a node near the leaf-axil. Usually a number of structures are met with there arranged in a transverse row. In Benincasa, cerifera, for example, in a ground plan of the node, beginning from the left, we found the following:—a tendril, a vegetative bud, a flower, a glandular structure looking like a rudimentary leaf. The last structure is absent in some species, and has a different form in some others. These differences would be indicated at the proper places.
Methods
In addition to free-hand sections other methods were also employed in the investigation. In some cases complete series of
