The Anatomy o/Dioon edule, LincH. 229 
possible that the young cortical cells immediately inside the phellogen 
contain the hyphse of an endophytic fungus, or bacteria ; these 
facts, however, could not be definitely determined, since the roots 
of the specimen examined were too long exposed before fixing, and 
consequently were in a bad stage of preservation. Should the 
suggestion prove to be correct it would fall into line with the facts 
observed by Life in Cycas revoluta 1 . All that can be definitely 
stated at present is that these cells are in a distinctly disorganised 
condition, and that their contents are stained deeply with methylene 
blue. 
General Considerations. 
Dioon edule, so far as the anatomy is concerned, appears to 
occupy a place among living Cycads very close to Stangeria paradoxa ; 
(i.) in the stem anatomy as described by Solms-Laubach ; (ii.) in the 
amount and distribution of the centripetal wood in the peduncle ; 
and (iii.) in the presence of cortical strands in the base of the 
peduncle. 
The view that, in the majority of Cycads, the cone is terminal, 
is based primarily on the obviously apical position of the mega- 
sporophylls of Cycas, and on the peculiar disposition of the vascular 
tissues of the peduncular cylinder in Stangeria, which we have also 
found in Dioon edule. The presence of cortical cauline bundles in 
the peduncle seems to indicate that the cone was not always so 
sharply marked off from the trunk as it is at present in the majority 
of Cycads. The monopodial growth of the trunk in Encephalartos 
Altensteinii and other species 2 is clearly a later development, and is 
connected with the production of several cones simultaneously. 
In conclusion we must express our thanks to Professor Seward 
for valuable help and suggestions throughout this investigation, and 
to Mr. Irwin Lynch for kindly giving information as to the history 
of the specimen. 
1 Bot. Gaz., XXXI., p. 265, 1901. 
’ Pearson. Trans. S. Afr. Phil. Soc., XII., p. 345, Dec., 1906. 
