300 BOTANICAL GAZETTE [APRIL 
inhabit moist places and have relatively wide spring tracheids, 38 p 
in the Pacific species, and 40 pw in T. taxifolia of the moister climate 
of Western Florida. 
Sequoia sempervirens (55 wu), which not only has larger leaves 
but also grows in a warmer and damper climate and moister soil 
than S. gigantea (39 m), exceeds all other measures of North Ameri- 
can Coniferae in width of spring tracheids. 
Of the two Pacific species of Chamaecyparis, C. Lawsoniana 
(18 uw) has unexpectedly narrow spring tracheids, for it grows prefer- 
ably on moist soil. Compared with it, C. mutkaensis has wider 
spring tracheids (25.5 ~) and grows in cooler and much moister 
regions, where it is limited to places having the moistest of air. 
Still wider spring tracheids are those of the Atlantic C. thyoules 
(32 uw), though it grows in cold swamps. 
Cupressus arizonica (25 ), living in the driest region (Mexican), 
is likewise the species with narrowest spring tracheids. The three 
other species measured are Californian, and the one with narrowest 
spring tracheids, C. Macnabiana (30 4), appears to be the one of 
the least moist habitat, for C. Goveniana (32 mu) is said to occur often 
on the banks of streams, while C. macrocarpa (39 u) is constantly in 
damp sea air. Yet this last species can be used with Pinus insignis 
to fix sand dunes, and its roots can be laved with sea water, so that 
without further investigation it is impossible to say that Cupressus, 
as a whole, definitely favors the view here propounded. 
The American species of Abies, whose tracheids have been 
measured, neither clearly support nor oppose the view. True it is 
that A. Patieersd de (33.5), the species that is nearly alpine and is 
described as “‘alpine,”’ has with one exception the narrowest spring 
tracheids, but that exception is A. Fraseri (30.5 «), Which grows 0D 
moist slopes in moist cool air. So far as habitat is concerned, there 
appears to be no reason why A. Fraseri (30 u) should have much 
narrower tracheids than the more northern Atlantic form A. 4a 
samea (40 u), which indeed often grows in swamps, and sometimes 
even sphagnum swamps, unless, indeed, the cause be the same as 
that already suggested in connection with the parallel cases of 
Pinus Banksiana and P. resinosa; apparently A. balsamea and P. 
Banksiana are found growing together. 
