Another side of the question remains to be considered. The word variety, as is now becoming generally recognized, has no special meaning whatever. But here it is assumed in the clearly defined sense of a systematic variety, which includes all subdivisions of species. Such subdivisions may be, from a biological point of view, elementary species and also be eversporting varieties. They may be retrograde varieties, and the two alternating types may be described as separate varieties. It is readily granted that many writers would not willingly accept this conclusion. But it is simply impossible to avoid it. The two forms of the water-persicaria must remain varieties, though they are only types of the different branches of a single plant. If not, hundreds and perhaps thousands of analogous cases are at once exposed to doubt, and the whole conception of systematic varieties would have to be thrown over. Biologists of course would have no objection to this, but the student of the flora of any given country [436] or region requires the systematic subdivisions and should always use his utmost efforts to keep them as they are. There is no intrinsic difficulty in the statement that different parts of the same plant should constitute different varieties. In some cases different branches of the same plant have been described as species. So for instance with the climbing forms of figs. Under the name of _Ficus repens_ a fine little plant is quite commonly cultivated as a climber in flower baskets. It is never seen bearing figs. On the other hand a shrub of our hothouses called _Ficus stipulata_, is cultivated in pots and makes a small tree which produces quite large, though non-edible figs. Now these two species are simply branches of the same plant. If the _repens_ is allowed to climb up high along the walls of the hothouses, it will at last produce stipulate branches with the corresponding fruits. _Ficus radicans_ is another climbing form, corresponding to the shrub _Ficus ulmifolia_ of our glasshouses. And quite the same thing occurs with ivy, the climbing stems of which never flower, but always first produce erect and free branches with rhombic leaves. These branches have often been used as cuttings and yield little erect and richly flowering shrubs, which are known in [437] horticulture under the varietal name of _Hedera Helix arborea_.