128 Dunn— A Key to the Labi at ae of China. 



are probably better represented in our herbaria than most 

 others. The writer is reluctantly forced to the conclusion that 

 our present knowledge -does not warrant the drawing up of any 

 such scheme of plant areas for China, and the following sugges- 

 tions are merely an indication of some obvious distribution lines 

 which appeared in the preparation of the work. The apparent 

 distribution along lines is doubtless due to the fact that, com- 

 pared with the great bulk of the empire, the areas collected in are 

 but isolated points, and the attempt to trace out an area of 

 distribution results in lines connecting them. 



i. Commencing then from Yunnan, the south-west corner 

 of China, and probably the richest province in Labiates, many 

 species (such as Leucas mollissima and Teucrium japonicuni) 

 extend due eastwards along the dry hills of S. China as far as 

 Hainan and Kwangtung and northwards as far as E. Szechuen 

 and Hupeh through Kweichow. Teucrium quadrifarium and 

 Stachys kouyangensis, starting from the same province, pursue 

 a north-eastern line, reaching as far as the Yangtze in lower 

 , while such species as Plectranthus ternifolius, though 

 and characteristic in the southern uplands, extend 

 no further north than Kweichow. Elsholtzia communis and E. 

 polystachya, avoiding on the other hand the eastern part of this 

 area, seem to follow the dry grassy mountain pastures through 

 the centre of China as far as the middle of the northern boundaries 

 in Shensi and Chili. 



2. While the above species follow lines radiating out from 

 Yunnan through the half quadrant east to north-east, many 

 others, such as Orthosiphon rubicundus, Plectranthus Coetsa, 

 Salvia hians, and Nepeta lamiopsis, are found to extend from 

 Yunnan due north along the bare stony pastures which flank 

 the lofty mountain ranges of Tibet as far as Ta-chien-lu in E. 

 Szechuen. Dracocephalum tanguticum and D. heterophyllum 

 reach still further north on the same line, running down to the 

 lesser altitudes of Kansu ; while the peculiar group of Elsholtzia 

 species, with woolly flower-spikes, is represented by a succession 

 of forms along the same range (viz. E. ianthina in Kansu, 

 E. calycocarpa and E. eriostachya further south). All the species 

 of north and south extension show, as usual, increasing altitude 

 with decreasing latitude. 



3. Coming now to denizens of damp and shady places which 

 radiate from the south-west, Pogostemon fraternus and P. glaber, 

 Scutellaria discolor, Craniotome versicolor, and Leucosceptrum 

 canum reach from India only as far as the shady forests of S. 

 Yunnan; Dysophylla verticillata and D. auricularia extend 

 thence due eastwards to Kwangtung, while D. linearis reaches 

 north-eastwards to Kweichow. Scutellaria rivularis has in the 



