IV. Selection of elementary species. 92 Cereals. Le Couteur. Running out of varieties. Rimpau and Risler, _Avena fatua_. Meadows. Old Egyptian cereals. Selection by the Romans. Shirreff. Hays. C. RETROGRADE VARIETIES. V. Characters of retrograde varieties. 121 Seed varieties of pure, not hybrid origin. Differences from elementary species. Latent characters. Ray-florets of composites. [xiii] Progressive red varieties. Apparent losses. _Xanthium canadense_. Correlative variability. Laciniate leaves and petals. Compound characters. VI. Stability and real atavism. 154 Constancy of retrograde varieties. Atavism in _Ribes sanguineum Albidum_, in conifers, in _Iris pallida_. Seedlings of _Acacia_. Reversion by buds. VII. Ordinary or false atavism. 185 Vicinism or variation under the influence of pollination by neighboring individuals. Vicinism in nurseries. Purifying new and old varieties. A case of running out of corn in Germany. VIII. Latent characters. 216 Leaves of seedlings, adventitious buds, systematic latency and retrogressive evolution. Degressive evolution. Latency of specific and varietal characters in wheat-ear carnation, in the green dahlias, in white campanulas and others. Systematic latency of flower colors. IX. Crossing of species and varieties. 247 Balanced and unbalanced, or species and variety crosses. Constant hybrids of _Oenothera muricata_ and _O. biennis_. _Aegilops_, _Medicago_, brambles and other instances. X. Mendel's law of balanced crosses. 276 Pairs of antagonistic characters, one active and one latent. _Papaver somniferum_. [xiv] _Mephisto Danebrog_. Mendel's laws. Unit-characters. D. EVERSPORTING VARIETIES. XI. Striped flowers. 309 _Antirrhinum majus luteum rubro-striatum_ with pedigree. Striped flowers, fruits and radishes. Double stocks. XII. "Five leaved" clover. 340 Origin of this variety. Periodicity of the anomaly. Pedigree-cultures. Ascidia. XIII. Polycephalic poppies. 369 Permanency and high variability. Sensitive period of the anomaly. Dependency on external conditions. XIV. Monstrosities. 400 Inheritance of monstrosities. Half races and middle races. Hereditary value of atavists. Twisted stems and fasciations. Middle races of tricotyls and syncotyls. Selection by the hereditary percentage among the offspring.