248 E, D. Merrill 



are in large part with the genera and species characteristic of 

 the tropical lands bordering the western Pacific. The purpose of 

 this paper is not to theorize concerning how or when these vari- 

 ous types, or their ancestors, reached Polynesia, but rather to 

 point out certain obvious facts in present-day distribution and 

 briefly to discuss the bearing that our limited knowledge of the 

 geological history of the Malaysian region has on this problem. 

 The so-called monsoon region in the Asiatic tropics has its 

 typical flora, and no sharp distinction may be drawn between 

 that of tropical Asia and that of the great archipelago that lies 

 between Asia and Australia. Whether many of the genera char- 

 acteristic of this region originated in what is now continental 

 Asia and migrated into Malaysia, or vice versa, is a question that 

 can scarcely be settled definitely and is perhaps of slight impor- 

 tance; unquestionably there have been extensive intermigrations 

 in both directions. We do know, however, that there are a num- 

 ber of characteristic Asiatic (continental) types in Malaysia, 

 occurring at both low and high altitudes, and that these types, as 

 a rule, do not reach Polynesia. Some of the numerous Asiatic 

 genera having indigenous representatives in Malaysia are : Taxus, 

 Pinus, Agrostis, Anthoxanthum, Bromus, Deschampsia, Muhl- 

 enbergia, Poa, Asparagus, Lilium, Ophiopogon, Salix, Ulmus, 

 Arenaria, Anemone, Ranunculus, Thalictrum, Sedum, Astilbe, 

 Deutzia, Sycopsis, Photinia, Rosa, Gleditschia, SJ^immia, Buxus, 

 Sarcococca, Pistacia, Berchemia, Hypericum, Viola, Daphne, Ac- 

 anthopanax, Sanicula, Primula, Lysimachia, Fraxinus, Ligus- 

 trum, Acer, Gentiana, Sweertia, Trigonotis, Vaccinium, Rhodo- 

 dendron, Gaultheria, Ajuga, Mo si a. Salvia, Alectra, By t ho phy- 

 lum, Hemiphragma, Sopubia, Lonicera, Peracarpa, Ainsliaea, 

 Anaphalis, Aster, Cirsium, Lactuca, and Solidago. There are 

 many others both at low and at high altitudes. 



