Professor Millardet of Bordeaux first called attention to the value of that part of the cane known as the diaphragm as a means of distinguishing species. The cane of the grape vine contains a large pith, and in most species this pith is interrupted by woody tissue at the joints; this woody tissue is the _diaphragm_. The presence or absence of the diaphragm and its thickness are of taxonomic value. In Rotundifolia, the southern Fox grape, the diaphragm is absent; in Riparia, the Riverbank grape, it is very thin; in Rupestris it is slightly thicker; while Cordifolia, Aestivalis, and Labrusca have thick diaphragms. This character is studied best in the year-old canes of the grape. The color-plate of canes shows the range in thickness of diaphragms as they occur in several species. [Illustration: V. RUPESTRIS V. RIPARIA V. LONGII V. CHAMPINI V. LABRUSCA V. VINIFERA V. AESTIVALIS BOURQUINIANA V. AESTIVALIS LINCECUMII V. BICOLOR V. AESTIVALIS V. BERLANDIERI V. ROTUNDIFOLIA V. DOANIANA V. LABR. × V. VIN. V. LABR. X V. RIP. SEEDS OF SPECIES OF VITIS [NATURAL SIZE AND ENLARGED]] The time of flowering is of considerable value in distinguishing species. Unfortunately it requires live plants and a certain time of year in order that this character be noted. The first American species to flower is Riparia. Rupestris flowers shortly after; next, Labrusca; Aestivalis a little later, although the Lincecumii variety of Aestivalis blooms slightly before Labrusca; Cordifolia is very late in coming into bloom, and Cinerea still later. Vinifera, the European grape, blooms shortly after Labrusca. The cultivated offspring of all wild grapes retain the blooming characters of the species from which they are derived. Other characters that have been found of great value are those connected with the seed. The ability to use the seed characters, however, cannot readily be acquired except by the use of an illustrated manual and some experience in selecting the seeds, as they are quite variable on the same plant. The weight of the seeds differs in different species, but varies so much inside the species that it is not of much value from a systematic standpoint. In general, it may be said that the Labruscas have the largest and heaviest seed of our American grapes; Riparia has the smallest seed, with Aestivalis occupying an intermediate position. The size of the seeds in Aestivalis, however, is more noticeable on account of the small size of the fruit. The color-plate illustrates the different characters to be found in grape seeds and a study of this plate with the technical descriptions of the several species will show how important seeds become in classifying grapes.