530 HutTcHINSON—THE MADDENI SERIES OF RHODODENDRON. 
subdivision of the genus. Species with revolute ptyxis must 
belong to a different division from those with convolute. So 
far as I know it has not hitherto been recognised, at any rate 
no importance has been attached to it. And perhaps one 
reason for its being overlooked may be found in an incident of 
the development. In many species with convolute leaves in 
bud the young leaves as they unfold from the bud at once become 
recurved at the sides. The change may be interpreted as 
providing protection to the underleaf surface. Its effect is 
that the leaves are revolute when they open, but this is a secon- 
dary not a primary position and is brought about in a very 
different way and at a different period i in development. Casual 
observation of the leaves at expansion would not supply evidence 
for deciding whether a revoluteness is primary or secondary 
and misinterpretation may have resulted. Rh. Dalhousiae of the 
Maddeni Series shows this passage from convolute to revolute 
very clearly. In the Triflorum Series Rh. chartophyllum does 
not show it nor does Rh. Davidsomanum, but many plants the 
identity of which is not yet clear and which have been called 
Rh. Davidsonianum show it 
“The Maddeni Series to which Rh. Valentinianum belongs is 
anaturalone. It has a wide area of distribution from Sikkim 
im the west through Bhutan, Siam, Burma, right across Yunnan 
to Mengtz in the extreme south-east of the province and in 
Kweichow. We may safely say that other species of it yet 
await discovery. Those we know of show interesting diver- 
gences within the phylum and through minor characters of 
relation fall into subordinate groups within the series. RA. 
ctliatum and Rh. Valentintanum make one such group—a Sikkim- 
Bhutan form on the west and a Yunnan form on the east, 
doubtless to be hereafter connected by the finding of linking 
forms in the intermediate region. Rh. Dalhousiae is a western 
type to which Rh. rhabdotum, Balt. f. et Cooper and other 
forms belong; Rh. Maddem itself is a western form with 
several microiorms; in the middle area of distribution Rh. 
formosum with Rh. Vettchianum represent a differential form ; 
and on the eastern area of distribution there are two promi- 
nent types centerimg one in Rh. cilitcalyx and the other in Rh. 
crassum. Notwithstanding divergences all the species conform 
to one prominent type of bud—the nest-bud it may be called 
because of the disposition of the surrounding leaves to the 
terminal bud. The last formed foliage-leaves of the shoot 
lying close up to and around the terminal bud are much 
weduced in size, have a broad somewhat sraainehe petiole 
adpressed to the bud and the shoot, and the stands 
off at seth right angles from the petiole. They are of a 
