ON THE RELATION OF PHYLLOTAXIS TO MECHANICAL Laws —-.20)1 
Distrieution or British Rust: a Correcrion. — I find, to my 
beginning of the Rubi list on p. 150 of this year’s Journal. The 
county of Edinburgh is there represented as haying no Rubus forms 
cept tdeus ‘clearly known” for it; whereas it ought to have 
i ifolius, R. sawatilis, and R. 
Chamamorus, long ago reported by Prof. Balfour. West Sutherland 
should also have been credited with five forms ‘clearly known,”’ 
instead of four. I hope, though I hardly dare expect, that there 
was laborious and often far from easy. ButI shall be glad if the 
quickened energies of our younger field-botanists make them quite 
out of date within the next few years.—W. Moyzz Rogers. 
NOTICES OF BOOKS. 
On the Relation of Phyllotawxis to Mechanical Laws. By Artuur H. 
Cuurcu, M.A., D.Sc. Part i. Construction by Orthogonal 
Trajectories, pp. 78 (September, 1901); 8s. 6d. Part ii. 
Asymmetry and Symmetry, pp. 79-211 (January, 1902); 5s. 
Williams & Norgate. 
8; bie 
covered the ‘‘final cause’’ in the principle that ‘ the transpiration 
which takes place in the leaves demands that air should circulate 
freely around them, and that they should overlap as little as 
ible.”’ 
In the general observations, page 22, the author says: ‘ Phyllo- 
taxis is the obvious and visible expression of more obscure plienomena 
in the growing apex, and must be referred to the first Zone of Growth, 
since in passing through the Zone of Elongation it may be funda- 
mentally altered in appearance. ... . It follows again that, for 
any spiral leaf arrangement that has passed through this second 
zone of elongation, no expression which is not a purely arbitrary 
and conventional one can be formulated.” 
: ference is made (page 31) to Sachs’s theory of the orthogonal 
Intersection of cell-walls, and to the remarkable similarity of the 
] 
Periclinal walls form a series of confocal parabolas crossed by a 
JOURNAL OF Borany.—V ou. 40. [May, 1902.) be 
