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NortH Haven Sanp PLains 611 
cross-section. The cortical tissue is made up of large, circular, 
colorless cells with rather thick walls and large intercellular spaces. 
Diameter of root, .46 mm. 
‘¢ ** central cylinder, .15 mm. 
fee -€€ largest vessels, 20 
LEPTILON CANADENSE. — Central cylinder contains three vessels 
in primary root. The endodermis is prominent, being made up of 
thin-walled cells that are rectangular in cross-section. The peri- 
cycle is formed of similar but smaller cells. The cortical tissue is 
very similar to the structure found in other composite roots, and 
consists of large thin-walled circular cells with large intercellular 
spaces. The outside layer has thicker walls. 
Diameter of root, .2 mm. 
‘* © central cylinder, .I mm. 
‘¢ ~~ ®_- largest vessels, 13 4 
ANTENNARIA NEGLECTA. — Transverse section of the xylem is a 
radial five-pointed star with phloem patches between the points. 
There are no large vessels. The endodermis is apparent, with 
cells nearly circular in cross-section and walls only slightly 
thickened. The pericycle is composed of similar but smaller cells 
The cortical tissue is made up of from fourteen to fifteen layers of 
rather large colorless cells oblong in transverse section. 
Diameter of root, .85 mm. 
*« _** central cylinder, : .25 mm. 
«« — * Jargest vessels, 17 
CHRYSANTHEMUM LEUCANTHEMUM.— Bundle has radial arrange- 
ment, with four xylem points and four phloem patches. The ves- 
sels are not large. Endodermis composed of thin-walled cells. 
The cortex is formed of very large colorless thin-walled paren- 
chyma-cells with large intercellular spaces. The peripheral layer 
is of a brown color. 
Diameter of root, .56 mm. 
“ ** central portion, .23 mm. 
‘« _ * largest vessels, 17 # 
bd ‘* cortical cells, 33 # 
ARTEMISIA CAUDATA. — One very large vessel in the center 
is Surrounded by several smaller vessels and lignified cells show- 
