VOLUME LII .- : NUMBER 2 
eRe 3 
BOTANICAL = AgELIE 
AUGUST rgri 
THE ADULT CYCAD TRUNK 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 146 
CHARLES J. CHAMBERLAIN 
(WITH TWENTY FIGURES) 
The structure and development of the cycad seedling is fairly 
well known in all the genera, and in Dioon, Ceratozamia, and 
Microcycas recent investigations have been particularly thorough; 
but some features of the adult trunk have hitherto escaped observa- 
tion, doubtless because such material is so difficult to obtain. Asa 
matter of fact, most of the descriptions are based upon dead con- 
servatory plants which had begun to decay and so had become 
worthless as ornamental specimens. 
Historical 
As early as 1829, BRONGNIART (1) described the stem of Cycas 
revoluta, and showed clearly that, in spite of the external habit, 
the woody structure was not at all related to that of palms, but 
resembled the wood of dicotyls, the principal difference being that 
Cycas had no bast or growth rings. 
Von Mout (2) studied a specimen of “Zamia latifolia” (En- 
cephalartos) 1.5 meters in height, and also a section of a large 
trunk of Cycas revoluta. He recognized the bast and described 
the histological characters of the wood, which he found to resemble 
that of dicotyls, except that it lacked true vessels. In the pith 
he found bundles like those of many cacti. There were no growth 
rings. 
81 
