Page:An introduction to physiological and systematical botany (1st edition).djvu/197

 Rh and Roxburghia viridiflora, t. 57. The greater clusters of vessels are generally called nervi or costæ, nerves or ribs, and the smaller venæ, veins, whether they are branched and reticulated, or simple and parallel.

Avenium, veinless, and enerve, ribless, are opposed to the former.

Trinerve, three-ribbed, is applied to a leaf that has three ribs all distinct from the very base, as well as unconnected with the margin, in the manner of those many-ribbed leaves just cited, as Blakea trinervis, ''Curt. Mag. t.'' 451.

Basi trinerve, three-ribbed at the base, is when the base is cut away close to the lateral ribs, as in Burdock, ''Arctium Lappa, Engl. Bot. t. 1228, Tussilago, t.'' 430 and 431, and the great Annual Sunflower.

Triplinerve, triply-ribbed, when a pair of large ribs branch off from the main one above the base, which is the case in