381 
thotaxy, and conversely.* The numerous seeds of these plants 
are too small to be easily compared together ; but the phyllotaxy 
or even the inflorescence serves as our best guide when other 
indications fail. A similar remark will apply to Oenothera bt- 
eunis, whose inflorescence curves to the right or left in the same 
direction as the leaves; though not always so easily determined 
as in Ladies’ Tresses. In some cases the seeds form a ready 
guide. For example, the Lima-bean is found on examination to 
have its cotyledons right and left, and two foliage leaves respec- 
tively dorsal and ventral (towards the dorsal and ventrai sutures 
of the pod). Now I found that the right margin of the dorsal 
leaf of the plumule of one seed overlaps the right margin of the 
ventral leaf, but the left margin of the dorsal leaf is overlapped by 
the left margin of the ventral leaf; and in another seed these 
relations are reversed. I also found that the seeds growing on 
one valve of the pod, being Nos. 1, 3,5, were all similar; whilst 
the seeds on the other valve, being Nos. 2, 4, were reversed. 
Thus the seeds on one margin of a carpel are found to be antidrom- 
ically related to those on the opposite margin. (I have not ex- 
amined whether successive pods from the same plant reverse these 
characters or not.) The pea showed its antidromy best when 
germinating, the emerging plumules of different seeds appearing 
under careful orientation to come up with opposing twists. The 
large plumule of the Almond seed can be seen by dissection to 
have two modes of torsion in different seeds. The akenes of Caf 
Sea exhibit antidromy, an interesting point in this plant as the op- 
Posite leaves render the determination otherwise difficult. The 
deeply enfolded endosperm of the coffee-bean is seen on a cross-sec- 
tion of different seeds to be in opposite directions; a mark which 
is a sure indication of similar diversity in the minute embryo. 
Even from the outside the two kinds of akenes are easily distin- 
Suishable, the figure of one reversing that of the other like one’s’ 
tight and left hand, thus proving that the two mericarps are rela- 
tively antidromic; and confirming the evidence already derived 
from the corn and Lima-bean, as to the origin of this character. 
* sep vaeeaa mane eee ee 
oo + Dextral phyllotaxy has the primary spiral traced by the insertion of the leaves 
directed like the thread of a common screw. With leaves overlapping at the margins, 
: dextral overlapping may produce sinistral phyllotaxy. 
