Propagated by seeds; by cuttings of half-ripened shoots. =Pentas.= _Rubiaceæ._ Propagated, with difficulty, by seeds or cuttings of half-ripened wood. =Pentstemon= (Beard-tongue). _Scrophularineæ._ Seeds, sown in pans and placed under a frame; or they are sometimes sown in the border where the plants are to stand. Also by division, and rarely by cuttings in summer. =Peperomia=, including Micropiper. _Piperaceæ._ Seeds. Cuttings of single joints of firm stems root easily in a peaty soil. Water sparingly. =Pepper, Black.= See Piper. =Pepperidge.= See Nyssa. =Pepper-grass=, Curled Cress (_Lepidium sativum_). _Cruciferæ._ Grown from seeds, either under glass for early crops or in the open air. =Peppermint= (_Mentha piperita_). _Labiatæ._ Divisions of the creeping and rooting stems are planted to multiply the plant, and plantations are renewed every three or four years. =Pepper=, =Red= or =Cayenne= (Capsicum). _Solanaceæ._ Seeds, sown out-doors, or in the north oftener started in the house. =Pereskia= (Barbadoes Gooseberry). _Cacteæ._ Seeds. Cuttings, as described under Cactus. _P. aculeata_ is much used as a stock for epiphyllums. _P. Bleo_ is sometimes used for the same purpose, as it is fully as good as the other species. Cuttings of _P. aculeata_ can be made a foot or more in length, and of sufficient size for immediate use, or, indeed, the graft may be inserted when the cutting is made. =Perilla=, Dentidia. _Labiatæ._ Sow the seeds in early spring in pans or boxes, and place in a gentle heat. Or southwards, seeds may be sown in the open. =Periploca.= _Asclepiadeæ._ Seeds. Increased mostly by layers or cuttings under glass, during summer or autumn. Root-cuttings succeed. =Periwinkle.= See Vinca. =Pernettya.= See Canarina. =Persea= (Alligator or Avocado Pear). _Laurineæ._ Seeds. Layers of ripened shoots may be made in autumn, or cuttings of firm shoots in spring, under glass. =Persimmon= (_Diospyros Kaki_ and _D. Virginiana_). _Ebenaceæ._ Stocks are readily grown from seed, and they usually attain sufficient size for budding the first year. The native persimmon (_Dispyros Virginiana_) is largely used as a stock for the Japanese persimmon or kaki. Imported stocks are occasionally employed, but the native is more vigorous, as a rule, and probably better. Persimmons are shield-budded the same as peaches, and they may be root-grafted and top-grafted by ordinary methods. =Persoonia=, Linkia. _Proteaceæ._ Propagated by cuttings of the ripened shoots, under glass. =Peruvian Bark.= See Cinchona. =Petalostemon= (Prairie Clover). _Leguminosæ._ Seeds and divisions. =Petunia.= _Solanaceæ._ Seeds, either in-doors or in the garden. Choice and double varieties are often increased by cuttings, which grow readily.