k 296 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



What influence this may have has not as yet been ascertained, but it is 

 curious that the number of the species greatly multiplies as we passE.S.E. 

 And what is more curious still, this property, whatever it be, seems to 

 continue to increase in value until Yunnan, a province of S.W. China, 

 becomes a new centre of Primula life and one even greater than that of 

 Sikkim. 



5. Yunnan may be said to lie between 23° and 27° north 

 latitude, thus entirely to the south of Sikkim, the link of connection 

 being 



G. Manipur and the Shan States, between 24° and 26° north latitude. 



We have this remarkable genus, which is dispersed along the great 

 mountainous backbone of the world, evolving into at least two great 

 types, as it is diffused from the Eastern Himalaya. Some years ago a 

 paper of mine on Primula was published in the Linnean Society's 

 " Journal." Since then I have seen cause to modify my views very greatly, 

 and the progress made, both in India and China, has practically antiquated 

 anything written so long ago as 1881. In my paper, however, I hinted at 

 a classification, based on the vernation, or method of folding and packing 

 of the leaves within the bud. This, I admit, is a distinction that botanists 

 are not likely to appreciate very much, since it can with difficulty be 

 detected in dried specimens. But I am addressing gentlemen who are 

 familiar with the cultivated Primulas, and I make bold to think they may not 

 object to a character that can be seen readily enough in the live plant. 

 Every one is familiar with the fact that in the common English Primrose 

 and Cowslip the two margins of the young leaves are rolled up inwards 

 towards the midrib on the under surface of the leaf. Equally familiar 

 is the fact that in the Auricula or " Dusty Miller " the one margin 

 of the leaf is rolled on the upper surface and within the opposite 

 margin. The former condition is denominated " revolute " and the latter 

 "convolute." They are conditions very largely characteristic of two of 

 the most important assemblages of Primroses in the world, namely the 

 Indian and the European. But while Europe possesses both types, no 

 example of a convolute Primrose has hitherto been met with in India, or, 

 I believe, in China. There is, however, a third condition of vernation 

 seen in Primula, namely " conduplicate." The leaves in this condition 

 are simply closed together, the upper surface of the right-hand side of 

 the blade being brought into contact with the left, like the closing of the 

 pages of a book. Now this condition prevails in Africa (Abyssinia more 

 especially) and is nu t with in two Indian species. And what is some- 

 what remarkable, conduplicate vernation is usually present in Primulas 

 that love a warm dry climate. The best-known examples of this series 

 are Primula floribunda of India and P. verticillata of Abyssinia. In 

 passing it may be observed that a hybrid recently appeared at Kew 

 between these two plants which has been much appreciated by cultivators. 



I now desire to invite your attention to one or two other structural 

 features of Primula that would seem to me to aid in a natural classifica- 

 tion of the species, and thus afford useful hints for cultivation. In many 

 species, whether the leaves be revolute, convolute, or conduplicate in bud, 

 the flowers, when borne on a scape, are either sessile or pedicellate. The 

 former gives origin to capitate (fig. 69), and the latter to umbellate forms 



