Rotundifolia is remarkably resistant to the attacks of all insects and to fungal diseases. The phylloxera do not attack its roots and it is considered as resistant as any other, if not the most resistant of all American species. The vines are grown from cuttings only with difficulty and this prevents the use of this species as a resistant stock. However, under favorable circumstances, and with skillful handling, this is a successful method of propagation. Under unfavorable circumstances, or when only a few vines are desired, it is better to depend on layers. As a stock upon which to graft other vines, this species has not been a success. There is great difficulty in crossing Rotundifolia with other species, but several Rotundifolia hybrids are now on record.
2. _Vitis Munsoniana_, Simpson. Florida Grape. Everbearing grape. Bird Grape. Mustang Grape of Florida.
Vine slender, usually running on the ground or over low bushes. Canes angular; internodes short; tendrils intermittent, simple. Leaves smaller and thinner than Rotundifolia and rather more circular in outline; not lobed; teeth open and spreading; petiolar sinus V-shaped; both surfaces smooth, rather light green. Cluster with more berries but about the same size as in Rotundifolia. Berry one-third to one-half the diameter, with thinner and more tender skin; black, shining; pulp less solid, more acid and without muskiness. Seeds about one-half the size of those of Rotundifolia, similar in other respects. Leafing, flowering and ripening fruit very late.
The habitat of _V. Munsoniana_ is central and southern Florida and the Florida Keys. It extends south of the habitat of Rotundifolia and blends into this species at their point of meeting. Munsoniana appears to be a variation of Rotundifolia, fitted to subtropical conditions. It is tender, not enduring a lower temperature than zero. In the matter of multiplication, it differs from _V. rotundifolia_ in that it can be propagated readily from cuttings. Like Rotundifolia it is resistant to phylloxera.
3. _Vitis rupestris_, Scheele. Mountain Grape. Rock Grape. Bush Grape. Sand Grape. Sugar Grape. Beach Grape.
A small, much branched shrub or, under favorable circumstances, climbing. Diaphragm thin; tendrils few, or if present, weak, usually deciduous. Leaves small; young leaves frequently folded on midrib; broadly cordate or reniform, wider than long, scarcely ever lobed, smooth, glabrous on both surfaces at maturity; petiolar sinus wide, shallow; margin coarsely toothed, frequently a sharp, abrupt point at terminal. Cluster small. Berries small, black or purple-black. Seeds small, not notched; beak short, blunt; raphe distinct to indistinct, usually showing as a narrow groove; chalaza pear-shaped, sometimes distinct, but usually a depression only. Leafing, blossoming and ripening early.