HILGARD—PHYLLOTAXIS. 51 
_ These elements do not actually stand on equal heights, but they 
ascend a very little on the axis, and always are at aeeus eccen- 
tric distances. 
__ In the labiate and personate tubular flowers, aie; sets of 5 are 
fused into a tube or neck, the /imbi or marginal expanses fre- 
quently, by the succession in which their suis are found auc, 
ping in the bud (prefloration), still declare the law of suc 
position, and probably of successive development.. Of chia a “very 
striking example is afforded by the gm of Nierembergia fili- 
caulis (Pole emonio-petuniacee ) of the gardens, where the 5 cor- 
ners of the rotate limbus, by their differenes, and succession ex- 
actly corresponding toa 3 disposition, a the same ive 
development as in the previous exam 
When a number of yn ce cycles ‘(successive disposition ) 
are approximated on a comparatively short axis—as on the pine | 
and pine-apple cones, the areolar impressions of the custard-apple, 
_the tabercles on the body and fruit of Cacti, in ny ae e sun- 
; ee cupules of acorns and t istles—by a we 
, ie bands of p iealial spiral files coils), comprising al demseat 
me prominent, alternating scleip and nied | ee succeed in 
num 
“second in steep ess, aa cm ‘of coils, ‘on; in tite. opposite oui: 
- the third, of 3; the fourth, of 5 coils; ‘the next of 8—each embra- 
a all elem ents, and in ‘the opposite sense eine ee 
_ ones in steepness 
_ Asan example: in the cone of the Norway pie we on a 
