Page:Popular Science Monthly Volume 66.djvu/214

210 From this cross many varieties were developed having all the colors known in beans.

The results of selection are often so simple as to form a mathematical rule, as in the case of Mendel's peas, which holds good with the tribe of peas (Pisum), but not generally with others so far experimented on. At other times they are so complicated that to follow them requires the highest skill, or may be utterly impossible.

A rubus (R. cratægifolius) from Siberia has fruit the size of a large half pea, brownish, seedy and tasteless. Hybridizing with the California blackberry (R. vitifolius), some of the hybrids have the best qualities of both berries combined, and a perfect balance of characters. Out of over five thousand second generation hybrid seedlings, every one is true to the seed. This refers to the Primus blackberry, which is now fully as true a species as any classified species of Rubus.

The raspberry has been hybridized with a strawberry: the results were thornless plants with trifoliate leaves looking like a strawberry plant and sending out underground stolons like the strawberry. At last, however, the plants send up canes three to five feet high bearing panicles of flowers more profuse in number than those on either parent. After flowering the plant never produces a berry, the fruit forming a small knob, with no effort at maturity.

In the hybrid of the strawberry and raspberry, the resultant plants bore three or four times as many flowers as the raspberry, seven or eight times as many as the strawberry.

Tendencies strong in the parent, even though for a time latent,