378 BOTANICAL GAZETTE [DECEMBER 
description is given of the floral structure, except that the fruit is 
‘‘a nut inclosed in a shuck or husk, the meat or embryo 
4-lobed.” 
Carya alba 
Root 
The primary structure may be studied from the thin lateral 
roots of the seedling. No secondary increase takes place during 
the first season; thus the epidermis and cortical parenchyma remain 
intact. The latter consists of about ten compact strata, and the 
endodermis is very thick-walled, representing a U-endodermis. 
A thin-walled pericambium of a single layer surrounds the pentarch 
stele, in which thick-walled conjunctive tissue is much in evidence, 
surrounding the vessels, and as a narrow group in the center of the 
stele. On the other hand, increase in thickness is readily mene: 
in the primary root of the seedling in its second year. In this 
epidermis and the primary cortex have become thrown off, pee ne 
by many layers of homogeneous, thin-walled cork of pericambial 
origin. Inside the cork is a narrow zone of thin-walled parenchyma, 
which surrounds a circular band of small strands of stereome 
(fig. 9, St), supporting the leptome (ZL) of the secondary mestome 
strands. There is now a continuous ring of cambium, from which 
the secondary mestome is developed, and the thickness of the root 
depends largely upon the presence of a very broad, central, thin- 
walled parenchyma, a true pith, containing starch in abundance, 
but no crystals. 
The development of stereome in the root deserves attention, 
since, so far as known, this tissue does not appear to be commonly 
represented in roots. In Carya it is a secondary structure, which 
seems to be the general case wherever it occurs in roots. As a 
primary structure the stereome is extremely rare, known only in 
a very few genera, Dirca, Anona, Celtis, etc., where it is developed 
in the primary leptome. 
STEM 
The apical internode of the seedling is densely covered with 
hairs of different types, unicellular, long, pointed, which are either 
single or developed in tufts; and large, sessile, pluricellular, glan- 
dular of peltate shape. The cuticle is smooth and the epidermis 
