HUTCHINSON—THE MADDENI SERIES OF RHODODENDRON. 7 
a V-shaped groove down the middle, whereas those with the 
elevated midrib have a convex upper surface and no groove, 
with one slight exception (R. megacalyx). 
Inflorescence.—This is a terminal loose umbellate truss, and 
from 1-flowered (R. pachypodum, R. supranubium) to 12- 
flowered (R. Nuttallit); the flower-bearing bud is usually 
broadly ovoid, and covered with numerous bud-scales leathery 
in texture, usually bluntly mucronate, and variously lepidote 
and glabrous or pubescent outside; in R. Nuttallii the flower- 
bearing bud just before opening is about 6 inches long (Hook., 
Bot. Mag., t. 5146) ; the length of the axis from which the bud- 
scales have fallen, and the approximation of the straw-coloured 
sears, vary considerably in separate species; the bracts and 
bracteoles subtending the individual pedicels have frequently 
fallen away at flowering time, and are so often absent from dried 
specimens that I have seen few to describe; as a rule they 
furnish little of specific importance ; the pedicels are lepidote, 
except in R. megacalyx, and they are both pubescent and lepi- 
dote in R. Dalhousiae and R. rhabdotum; they nearly always 
arise from approximately the same height (subumbellate) ; in 
R. lasiopodum they break off and leave a projecting “ foot ” 
like tomentose portion of the axis of the inflorescence. 
Calyx.—This varies from a mere undulate rim (R. lasiopodum) 
to very large (2.3 cm.), especially in subseries Megacalyx and 
in subseries Eumaddenia ; frequently the lobes (or the rim) are 
longer on the dorsal (adaxial) side; in subseries Ciliicalyx the 
lobes (or the rim) are very frequently bristly ciliate, but the 
degree of ciliation is evidently subject to considerable variation, 
and is sometimes present and absent even in the same inflores- 
cence (R. supranubium) ; in the other two groups the calyx is 
usually not ciliate, or if it is, then very softly and weakly so 
(R. Lindleyi) ; R. megacalyx (see fig. 4) is remarkable in having 
the calyx campanulate and lobed only to about the middle ; 
in nearly all the species the calyx is lepidote outside, especially 
towards the base. 
Corolla.—In shape more or less tubular or funnel-like, and 
always 5-lobed ; the presence or absence of scales on the outside 
of the tube furnishes a good specific character, and I have 
freely employed this feature in framing the key; the lobes are 
always lepidote down the middle and occasionally on the margin ; 
the corolla of R. Ludwigianum, in addition to being lepidote 
outside, is very softly and densely villous, whilst several more 
species of the Cilvicalyx group are minutely and softly pubescent 
outside the base of the corolla tube ; the colour of the corolla is 
white or white and flushed with rose, and a few (R. lasiopodum, 
and others) have a yellow blotch inside the base of the tube; 
