467 
twisted, and of another plant sinistrorsely. All the long leaves of 
all plants of Lypha (both species) have a sinistral twist, in this 
showing no antidromy; but the mode of overlapping of the mar- 
gins of their leaves near the nodes, which is the same for all the 
leaves of one plant, is contrary as between different plants. If 
this is a case of genuine antidromy, it is an argument against the 
view that the ovules of Typha arise terminally on the floral axis, 
a view which on other grounds has been doubted. 
In the somewhat decussate leaves of Paulownia, and of the 
Shaded branches of forsythia, we can trace a spiral twist by fol- 
lowing any one of the leaf orthostichies (they twist all in one di- 
rection about Princeton, where the plants are not propagated from 
seeds), But the branches of /orsytiia when exposed to the sun- 
light lose their decussation and have all their leaves in two hori- 
zontal rows, thus demonstrating the controlling influence of the 
light. I believe that in a similar way many of our plants, as Elm, 
Beech and Morning-glory, have sacrificed their primitive phyllo- 
taxy to the allurements of sunshine. 
The Coniferae furnish an example showing how growth may 
Supersede or even reverse the primitive order of parts. The young 
cones of Picea, Tsuga and other trees have the same spiral caste 
as the phyllotaxy, when we estimate their spirality by taking the 
longer of the two dominant curves as we do for the phyllotaxy. 
But after the cones open to give exit to the seeds, there comes a 
displacement of the scales, producing a false spirality in the con- 
trary direction; thus the same tree, or even the two sides of a 
half-opened cone may present a quasi-antidromy. This may pos- 
Sibly be the explanation of published observations as to Coni- 
fers having antidromic cones on the same tree.* 
The cases of Arum, Jris and Juncus were previously referred 
to as giving antidromic plants produced not by seeds but by divi- 
Sion of the same rootstalk. A more curious case of diversity 
Within the same plant is that of Bilsted (Liguidambar Styracifiua), 
Which is cited in books as having opposite spirals in stem and 
branches. Every branch of this tree is true to its own phyllotaxy, 
with a 2 divergence, dextrorse or sinistrorse for each, and this per- 
Sisting through the annual innovations, whose crowded scale-scars 
Verreepe sane 
* American Naturalist, August, 1873. 
