Weeping varieties afford similar instances. _Sophora japonica pendula_ originated about 1850, and _Gleditschia triacanthos pendula_ some time later in a nursery at Chateau-Thierry (Aisne, France). In the year 1821 the bird's cherry, or _Prunus Padus_, produced a weeping variety, and in 1847 the same mutation was observed for the allied _Prunus Mahaleb_. Numerous other instances of the sudden origin of weeping trees, both of conifers and of others, have been brought together in Korshinsky's paper. This striking type of variation includes perhaps the best examples of the whole historical evidence. As a rule they appear in large sowings, only one, or only a few at a time. Many of them have not been observed during their youth, but only after having been planted out in parks and forests, since the weeping characters show only after several years. The monophyllous bastard-acacia originated in the same way. Its peculiarities will be dealt with on another occasion, but the circumstances of its birth may as well be given here. In 1855 in the nursery of Deniau, at Brain-sur-l'Authion (Maine et Loire), it appeared in a lot of [618] seedlings of the typical species in a single individual. This was transplanted into the Jardin des Plantes at Paris, where it flowered and bore seeds in 1865. It must have been partly pollinated by the surrounding normal representatives of the species, since the seeds yielded only one-fourth of true offspring. This proportion, however, has varied in succeeding years. Briot remarks that the monophyllous bastard acacia is liable to petaloid alterations of its stamens, which deficiency may encroach upon its fertility and accordingly upon the purity of its offspring. Broom-like varieties often occur among trees, and some are known for their very striking reversions by buds, as we have seen on a previous occasion. They are ordinarily called pyramidal or fastigiate forms, and as far as their history goes, they arise suddenly in large sowings of the normal species. The fastigiate birch was produced in this way by Baumann, the _Abies concolor fastigiata_ by Thibault and Keteleer at Paris, the pyramidal cedar by Paillat, the analogous form of _Wellingtonia_ by Otin. Other instances could easily be added, though of course some of the most highly prized broom-like trees are so old that nothing is known about their origin. This, for instance, is the case with the pyramidal yew-tree, _Taxus baccata fastigiata_. [619] Others have been found wild, as already mentioned in a former lecture. An analogous case is afforded by the purpleleaved plums, of which the most known form is Prunus Pissardi. It is said to be a purple variety of _Prunus cerasifera_, and was introduced at the close of the seventies from Persia, where it is said to have been found in Tabris. A similar variety arose independently and unexpectedly in the nursery of Spath, near Berlin, about 1880, but it seems to differ in some minor points from the Persian prototype.