Species and Varieties, Their Origin by Mutation

by Hugo de Vries

Viola tricolor, Draba verna, Primula acaulis, and other examples. Euphorbia pecacuanha. Prunus maritima. Taraxacum and Hieracium.

III. Elementary species of cultivated plants. 63

Beets, apples, pears, clover, flax and coconut.

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.