274 DR. P. GROOM ON THE LONGITUDINAL 
the main axis (12 mm.) represented the displacement of one leaf upwards from what 
would be the third node if the ancestral opposite phyllotaxis were preserved. There 
should therefore have been at the summit of the segment only one leaf, the upwardly 
displaced one, separated from its predecessor by 180°; this leaf was present but exactly 
opposite to it, and therefore exactly superposed on the immediately preceding leaf was 
another leaf (which subtended the branch termed 5th* (IV*)) The result is the same 
as if the original 3rd node, with leaves A and B, were first to produce leaf A, and then 
were to elongate and produce, higher up, not only leaf B, but also a repetition of leaf A 
superposed on this. It is of great interest to note that the branch subtended by this, 
so to speak, repeated leaf showed at its base a reversion to the original opposite 
phyllotaxis, but higher up a type of longitudinal symmetry resembling that of the 
6th branch (IV'), which was inserted at the same level. 
The subcurves of the branches show clearly how closely those of the successive pairs 
agree with each other but differ from those of their predecessors or successors. 
Atriplex rosea 110. (Curves 2m, 2 1-111.) 
2m 2t 2r 
Total length. 
Man stom ... un 22 |4 8|0 |175|0 | 17117 | 75| 22 225| 13 | 7 |Bud. 165 
de Benhül) 4286 5 | 00 16 UO 12 190] 818 1... 1-1 1504 9» 185 
Zu |. QD w a [e| S17 1111. 1G.) 1e 1252 2B 
{ Bd , GED (AS {æ a9 Lbs ie |19| eib o | ee fe ee 2228 
4th ,, (II)..40 10 | 95 185,40 18 |25|10|9 |Bud| ..|..|.-]-- 195 
fe oo GV) Hue em ied 1T] 6. |.|.|-| pl 
6th  , (IV)..375 275| 34 135 14. | 4:5 
l Th, (V) ..97 1175| 2718516 |Bud. 
8th  , (V) ..(A dwarf shoot consisting of a cluster of flowers.) 
"uh , UD... | 6 | 8 |Bud. 
10th =, (VI)..965,6 6 | Bud. 
llth , (VD. - 
