First of all we may mention three perennial forms called by him _Viola tricolor ammotropha_, _V. tricolor coniophila_ and _V. stenochila_. The typical _V. tricolor_ is an annual plant; sowing itself in summer and germinating soon afterwards. The young plants thrive throughout [42] the latter part of the summer and during the fall, reaching an advanced stage of development of the branched stems before winter. Early in the spring the flowers begin to open, but after the ripening of the seeds the whole plant dies. The three perennial species just mentioned develop in the same manner in the first year. During their flowering period, however, and afterwards, they produce new shoots from the lower parts of the stem. They prefer dry and sandy soils, often becoming covered with the sand that is blown on them by the winds. They are prepared for such seemingly adverse circumstances by the accumulation of food in the older stems and by the capacity of the new shoots to thrive on this food till they have become long enough to reach the light. _V. tricolor ammotropha_ is native near Ystad in Sweden, and the other two forms on Gotland. All three have narrowly limited habitats. The typical tricolored heartsease has remained annual in all its other subspecies. It may be divided into two types in the first place, _V. tricolor genuina_ and _V. tricolor versicolor_. Both of them have a wide distribution and seem to be the prototypes from which the rarer forms must have been derived. Among these latter Wittrock describes seven local types, which [43] proved to be constant in his pedigree-cultures. Some of them have produced other forms, related to them in the way of varieties. They all have nearly the same general habit and do not exhibit any marked differences in their growth, in the structure and branching of the stems, or in the character of their foliage. Differentiating points are to be found mainly in the colors and patterns of the flowers. The veins, which radiate from the centre of the corolla are branched in some and undivided in others; in one elementary species they are wholly lacking. The purple color may be absent, leaving the flowers of a pale or a deep yellow. Or the purple may be reddish or bluish. Of the petals all five may have the purple hue on their tips, or this attribute may be limited to the two upper ones. Contrasting with this wide variability is the stability of the yellow spot in the centre, which is always present and becomes inconspicuous only, when the whole petals are of the same hue. It is a general conception that colors and color-markings are liable to great variability and do not constitute reliable standards. But the cultures of Wittrock have proved the contrary, at least in the case of the violets. No pattern, however quaint, appears changeable, if one elementary species only is considered. Hundreds of plants from seeds [44] from one locality may be grown, and all will exhibit exactly the same markings. Most of these