Potato (Solanum tuberosum). Solanaceæ.
Tubers, either whole or variously divided. Also rarely stem cuttings. (See [page 52].)
Potentilla, including Horkelia, Sibbaldia (Cinquefoil, Five-Finger). Rosaceæ.
Seeds, layers, divisions, green cuttings.
Poterium, including Sanguisorba (Burnet). Rosaceæ.
The herbaceous kinds are increased by seeds. The shrubs are raised from soft cuttings, under glass.
Premna, Baldingera. Verbenaceæ.
Seeds and soft cuttings.
Prickly Ash. See [Zanthoxylum].