42 



Of the two Papuan species in BackJiousia, another of the so-called 

 Australian endemic genera, one was described by Ridley from Mt. Carstensz, 

 to which a second, one of the commonest trees in the Arfak, is now added. 

 Both have normal calyx-lobes, while the Australian species show a secondary 

 petaloid development of the lobes, evidently derived in character, though 

 previously considered a generic distinction. 



The same case may be quoted for Didiscus, where the older types, 

 according to the Monographer, 1 showing a normal calyx, occur in Malaya 

 and New Guinea, with one species in N. Australia, whereas those with 

 aborted calyx-lobes, by far the most numerous, are known from the rest of 

 that continent, with one species from some Polynesian Islands. 



Further evidence is also forthcoming in interesting new records of 

 genera not previously known from New Guinea, namely, Hibbertict, hitherto 

 considered Australian and New Caledonian ; Centrolejns, abundant at 7000' 

 and 9000', connects New Guinea with the open summit of Kinabalu in 

 N. Borneo at 13,000', Mt. Halcon in the Philippines at 7000', and S. China 

 on the one hand, and Australia and New Zealand on the other ; while the 

 genus Patersonia, supposed on inadequate knowledge to be endemic Australian, 

 shows the same distribution, with the exception of S. China, and now in- 

 cludes three very distinct Mahiyan mountain types. 



In the case of species, Gahnia psittacorum, abundant everywhere in the 

 Arfak from 7000', is the first record for Malaya of a plant widely distributed 

 in E. Australia to Tasmania. 



2. WIDE DISTRIBUTION IN NEW GUINEA OF ENDEMIC 

 MOUNTAIN TYPES. 



In considering questions bearing on the phytogeography of New Guinea, 

 as a whole, it is important to take into consideration the fact that it is a 

 country of 786,000 km. in area (23, i. 14, i), most of which is mountainous in 

 character and undisturbed in condition. A huge region of vast ranges, in 

 which all intercourse between the relatively few and scattered inhabitants 

 is not only restricted by natural barriers, but also by the many different 

 languages, no two tribes having a common speech, even when living in 

 apparent proximity on the same range of mountains. Both these facts have 

 effectually debarred outside penetration into the mysterious back-country. 



Though our knowledge of the plant-covering of these mountains is 

 extremely limited, such phytogeographical exploration so far accomplished 

 points, as would be expected under such virgin conditions, to the homogeneity 

 and stability of the flora as a whole. This fact is evinced in the pronounced 

 endemism and wide distribution throughout the whole country, further 



1 Domin, K., " Monographie der Gattung Didiscus (DC.)." Sitz. Kon. bohm. Ges. d. 

 Wise. ii. Cl. (1908) 21. 



