206 BOTANICAL GAZETTE [SEPTEMBER 
Characteristic jeatures—Under this heading may be placed the 
occurrence of two cotyledons, the hypogean character of germination, 
the thick tap root, centripetal wood in the cotyledons and leaves, 
girdling, and numerous mucilage ducts. 
Character upon which the seedlings may be divided into two 
groups.—This is the presence or absence of anomalous thickenings 
or cortical vascular strands. They occur in Cycas, Bowenia, and 
Encephalartos; they are said to be absent in Zamia, Dioon, Macro- 
zamia, and Ceratozamia, though they were found in the mature stem 
of Macrozamia Fraseri by WorspEtt. Microcycas remains to be 
reported upon. 
Features peculiar to certain genera.—We may place here the single 
cotyledon reported for Ceratozamia, the three cotyledons of En- 
cephalartos, concentric bundles in the base of the cotyledon of Stan- 
geria, the polystele in the earliest formed part of the axis of Enceph- 
alartos, and mucilage ducts in the root of Dioon, 
The present series of studies aims in the first part to add to the 
list a detailed account of Ceratozamia, Microcycas, Dioon spinulosum, 
and species of Zamia; and in the second part to extend the invest!- 
gation to the conifers by examining some juveniles of each of the 
great groups. Podocarpus, Keteleeria, Cunninghamia, P inus edule, 
P. Banksiana, and a few others, as well as the cycads mentioned, are 
well under way. 
Ceratozamia 
In 1846 BRoNGNIART (2) gave the generic and specific names “i 
Ceratozamia mexicana, a “new cycad from Mexico.” He desctt 
the adult forms and the ovulate and staminate strobili. In 187° 
WarMING (15) reported the monocotyledonous character of ve 
embryo. In 1872 Van TrecHEM (13) examined four seedlings = 
found a thick scale enclosed by the sheathing base of the single ihe 
ledon, and, in turn, enclosing a hairy foliage leaf with one 
vernation. One of the four seedlings was suspected by him of having 
the rudiment of a second cotyledon. He describes the root after 
xylem and phloem have reached their final position, and adie he 
number and derivation of the cotyledonary strands and early | ‘ 
traces; but in these respects, no two of the seedlings agree A” 
of mature stem, examined by Sotms-LAUBACH (12) in 1890, W# 
