Riparia is very resistant to phylloxera, the roots are small in size, hard and numerous and branch freely. The roots feed close to the surface and do not seem to be well adapted to forcing their way through heavy clays or a hardpan formation; but as such soils are unfavorable for all grapes, this character is of little economic importance. Riparia grows readily from cuttings and makes a good stock for grafting, and its union with other species is usually permanent. At the time when Riparias were first sent to France to be used as a stock in reconstituting the French vineyards, it was found that many of the vines secured from the woods were of too weak growth to support the stronger-growing Viniferas. On this account the French growers selected the more vigorous forms of the Riparias sent them to which they gave varietal names, as Riparia Gloire, Riparia Grand Glabre, Riparia Scribner, Riparia Martin and others. With these selected Riparias the graft does not outgrow the stock. Riparia is less resistant to rot than Aestivalis but somewhat more resistant than Labrusca. The foliage is rarely attacked by mildew. One of the chief failings of this species is the susceptibility of the leaves to the attack of the leaf-hopper. This defect is quite serious in some grape-growing regions. The Riparias are generally late in ripening and it is found that the fruit is better in quality in long seasons and that it should be left on the vines as late as possible. There are some early ripening varieties of this species, however. =VITIS RIPARIA PRÆCOX= Engelmann. =1.= Price, =1830=:194. V. ODORATISSIMA; _June Grape._ =2.= Engelmann, _Mo. Ent. Rpt._, =1872=:61. =3.= Ib., _Bush. Cat._, =1883=:18. JUNE GRAPE. =4.= Bailey, _Am. Gard._, =14=:353. 1893. V. VULPINA, var. PRÆCOX; _June Grape_; _V. riparia_, var. _præcox_. =5.= Ib., _Gray's Syn. Fl._, =1=:422. 1897. V. VULPINA, var. PRÆCOX; _June Grape_. The first record of Riparia Præcox is a statement by Prince in 1830 that Nuttall had told him that the June Grape growing on the Mississippi was the true _Vitis odoratissima_ (a sweet scented Riparia which later botanists have not recognized as a distinct species). In 1872 Engelmann refers to it, saying that it grows on rocky river banks in the vicinity of St. Louis and that it is brought to market in July. He says further in the _Bushberg Catalogue_ that from the first of July on, ripe fruit is to be found through August and September. Bailey states in the _American Gardening_ that Engelmann in his herbarium had given this variety the name _præcox_ but did not know whether it had been published or not. The variety differs from the typical form of Riparia only in the ripening season and possibly in the berries averaging smaller. The early ripening season might make it of horticultural importance as a breeding stock although in other respects the fruit characters are not such as would recommend it. 6. =VITIS TRELEASEI= Munson.[138]