40 JOURNAL OF THE ARNOLD ARBORETUM (vol. il 



ercd ill llic two widely separated regions. I am positive, howexer, that in 

 the evergreen Fagaeeae and Lauraceae many trees will be found eonspecific. 

 A eonerete example of this relationship is Pittosporuw (Japhniphylloidcs Hay. 



whieh grows on Ari-san and elsewhere in Formosa and on Mt. Omei and 



in neighboring mountains in western Szeeh'uan. Some of the Rubi in the 

 two regions are identical and like the Pittosporum are absent from eastern 

 China. Some types, Rhudodcndron Maricsii Ilemsl. & Wils. lor exam])le, 

 which have their western limits in Hupeh and southeastern Szeeh'uan are 

 found also in the eastern provinces of China and in Formosa. Among the 

 more unstable modern genera the species are numerous, local in distribution 

 and of minor importance in phytogeographical research. For such work old 

 types are more instructive and as their species are usually limited in num- 

 ber tliey are more easily dealt wilh. The absence in Formosa of such ty{;es 

 as Nyssaceae, Eucommiaceae, Cercidiphyllum, Euptelca, Magnolia and 

 Hamamelis is i)uzzling since they are a feature in central and western China. 

 But without magnifying unduly the anomalies we may obtain a ])ctter ]]er- 

 spective of the jiroblem of i^hytogeographical relationshi]) if we consider 

 a grouj) like the Conifers and Taxads of Formosa and com])are them with 

 their relatives in Jai)an, eastern China and western China. Of the four 

 species of Pinus in Formosa, one Hard Pine (P. taiwanensis Hay.) is 

 endemic, and is essentially a mountain species though on the east coast it 

 descends to below an altitude of 300 m. The other P. MoHsoniana Lamb. 

 is confined (o low altitude on the northwest and west-northwest parts, and 

 in China is found from sea-level to 1300 m. altitude in all but the colder 

 regions. The White Pine (P. morruonicola Hay.) is endemic, and the Nut 

 Pine (P. Armandi Franch.) though abundant in the central and western 

 regions is absent in eastern China but reappears on Yaku-shima, Tanega- 

 shima and the southern tip of Kyushu in Japan. The Abies of Formosa 

 {A. Kaicalcamn Hay.) is endemic but is closely related to Ahies Faxoniana 

 Rehd. c^ Wils. of northwest Szeeh'uan. The Picea (P. morrlsonicola Hay.) 

 is endemic but its nearest relative is P. WaLsonicma Masters of western 

 China. ^ The Tsuga of Formosa {T. viorrisonicola Hay.) is identical with T. 

 chiiicnsis Pritzel a1)undant in central and western China but absent from 

 eastern China. The Pseudotsuga (P. Wilsoniana Hay.), is eonspecific with 

 P. sincmiH Dode of Kweichou and Yunnan. The Keteleeria is A'. Daridkma 

 Beissn. .so abundant in central and western China uj) to lOCO m. altitude. 

 This is instructive since in eastern China grows A'. Fortunci .Mayr, a very 

 distinct si^ecies. The Cunninghamia of Formosa (C. Ko?n,shii Hay.) is 

 endemic and the other .sjiccies of the genus (C. lanccohda Hook.) is confined 

 to Chnui. The Taiwania first discovered in Formosa is now known to grow 

 wild in the cxtrem(> northwest border of Yunnan. The related Cryj)- 

 tomeria is purely Japanese being unknown as a wild tree in Cdiiua and 

 Formosa. Chamaecyparis, unknown in the continental areas of the Old 

 \V()rld is represented by the gigantic C.jormoscnds Matsum. and another 

 which is apj)areiitly identical with the Japanese C. ohttisa S. & Z. The 

 Libocedrus {L. macrolcpis IJenth. & Hook, f.) is confined in P^ormosa to the 



