BOTANIZING WITH THE OKINAWANS — WALKER 377 



Formerly, at least, sugarcane (pi. 3, lower) was the third principal 

 crop, grown only in the south, but the former sugar mills and the 

 market for the sugar produced are only now being restored. Although 

 there are many other crops, one is impressed by the dependence on 

 sweetpotatoes. This makes more serious the problem of combating 

 the recently introduced and seriously threatening sweetpotato weevil 

 and the sweet potato blight. When not cultivated, the cleared slopes 

 are planted, or at least often grow up in pines or other second -growth 

 forest trees. All are sources of fuel, and one is impressed by the im- 

 portant industry in the northern villages of hauling down from the 

 hills poles and small trees, cutting and splitting them into fuel size, 

 and stacking the wood on the roadsides, whence trucks may carry 

 it to the larger towns. This activity makes serious inroads on the 

 forests wherever they can be reached. Among the first invaders of 

 these cleared lands are, of course, various shrubs and weedy trees, 

 among them, perhaps, being Trema orientalis with banyans following 

 after, usually beginning as epiphytes and finally strangling and re- 

 placing the host trees. Sometimes camphor trees {Cinnamomum 

 camphora) or other useful species are planted. In the far north the 

 narrow, steep ravines filled with the light-green spreading leaves 

 of the fiber banana are a striking feature. The slopes between and 

 the headlands are spotted with dark-green cycads. 



Turning now to the higher slopes and more remote mountain peaks, 

 one finds an almost unbroken tropical evergreen jungle composed of 

 a great variety of trees, with understories of lesser trees, shrubs, and 

 vines. Epiphytes are not specially numerous, as in many tropical 

 jungles, but the ground is hidden under a well-developed herbaceous 

 cover. The most valuable trees for man's uses are various oaks, 

 Quercus, Lithocarpus; chestnut, Castanopsis lutchuensis; and several 

 laurels (Lauraceae), such as Machilus thunbergii, M. longifolia, Cin- 

 namomum japonicum, C. loureirii, and Actinodaphne lancifolia. 

 Equally sought after for timber are members of the tea family 

 (Theaceae) , such as Adinandra ryukyuensis, Camellia miyagii, Cleyera 

 japonica, Shima Imkiuensis, Ternstroemia gymnanthera, and Tut- 

 cheria virgata, and members of the persimmon genus (Diospyros) 

 in the ebony family (Ebenaceae) . A characteristic, easily recognized 

 tree is the native palm Arenga engleri. Indeed, these forests, which 

 the Japanese botanists characterize as laurisilvae, are rich in species. 

 Now and then we saw in the northern mountains remnants of planta- 

 tions of the Japanese cedar, or sugi, Cryptomeria japonica, but this, 

 probably the most valuable of all trees in Japan, is not indigenous 

 in the Eyukyus except in the northern islands, where it forms natural 

 forests at high elevations, notably on Yakushima. The central and 

 southern Ryukyus apparently lack sufficiently high, cool elevations 



