Rhus属樹種

Though there is no difference i n the quantity of the latex exuded from young stems and leaves of each species of Rhus plants found in Japan, in the old stems of Rh. vernicifera, latex exudes in most abundance, it is abundant also in Rh. semialata var. Osbeckii, but far less in the old steams of Rh. succedanea, Rh. silvestris, Rh. Toxicodendron var. vulgaris and Rh. trichocarpa. The colour of the latex differs both in the species and the various parts of the body of Rhus plants. The latex from the young leaf and stem of Rh. semialata var. Osbeckii is white, while in other species it is milkwhite. The colour of the latex from the old stem of Rh. vernicifera is ash-white, but pale yellow in the old stern of Rh. semialata var. Osbeckii. The latex in other species is colourless or light brown. The latex of Rh. semialata var. Osbeckii does not easily change its colour in the air, and has the character of strong viscocity and rapid solidification, but the latex in other species becomes black or varnish-black in a short time, and is inferior to the former in the viscocity and solidification. The latex of Rh. semialata v a r . Osbeckii is also different from that of other . species in its chemical characters: e.g. the latex in the other species is acid, but the latex in Rhus semialata var. Osbeckii is neutral, and the colour reaction of the latex with several reagents shows the latter to be notably different from that . of other species. The latex exuded from old stems of Rhus plants found in Japan :contains more or less. caoutchouc, albumen, urusiol or a similar substance and oxidase. Urusiol or the substance resembling i t appears to be the poison in the latex, and the Rhus plants may protect themselves from injury by animals by means of it. The caoutchouc in the latex may be useful for the healing of injured -portions of the plant.