206 BOTANICAL GAZETTE [September 



Characteristic features. — 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 Worsdell. 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 investi- 

 gation to the conifers by examining some juveniles of each of the 

 great groups. Podocarpus, Keteleeria, Cunninghamia, Finns edultf, 

 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 to 

 Ceratozamia mexicana, a "new cycad from Mexico." He described 

 the adult forms and the ovulate and staminate strobili. In 1870 

 Warming (15) reported the monocotyledonous character of the 

 embryo. In 1872 Van Tieghem (13) examined four seedlings and 

 found a thick scale enclosed by the sheathing base of the single coty- 

 ledon, and, in turn, enclosing a hairy foliage leaf with circinate 

 vernation. One of the four seedlings was suspected by him of having 

 the rudiment of a second cotyledon. He describes the root after the 

 xylem and phloem have reached their final position, and gives the 

 number and derivation of the cotyledonary strands and early leaf 

 traces; but in these respects, no two of the seedlings agree. A piece 

 of mature stem, .examined by Solms-Laubach (12) in 1890, was 



