14 LEITNERIACEAE. 
LEITNERIA. Corkwood. 
(Family Leitneriaceae). 
Little-branched tree-like shrubs 
with very soft and light wood: 
deciduous. Twigs round, rather 
stout: pith moderate, rounded, 
continuous, white. Buds solitary, 
sessile, rather small, ovoid, with 
about 3 exposed scales, or the up- 
per (floriferous) enlarged, oblong, 
or ellipsoid, and with a dozen or 
more exposed scales. Leaf-scars 
alternate, half-elliptical or some- 
what 3-lobed, slightly raised: bun- 
dle-traces 3: stipule-scars lacking. 
The North American corkwood, 
apart from the fact that its wood 
is very much lighter than that 
of any other native shrub or tree, 
is interesting in that it is the only 
representative of its family, not 
very closely related to any other 
; : group, and that it occurs locally 
in swamps from western Florida, where it was first found, to 
southern Missouri, apparently surviving from a time when 
the Mississippi carried much more water and spread over a 
greater delta than at present. Like the bald cypress, though 
occurring naturally in swamps, it is capable of successful cul- 
tivation in soil of ordinary dryness. 
On anatomical grounds, Van Tieghem and Lecomte, in 
the Bulletin de la Société botanique de France, 33:181, ally 
Leitneria with Dipterocarpaceae. Dr. Pfeiffer, in the Botani- 
cal Gazette, 53:119, finds in it a suggestion of derivation of 
catkin-bearing angiosperms from gymnosperms. 
Loosely gray-hairy: twigs purplish. L. floridana. 
