ANATOMY OP CERTAIN SPECIES OF ENCEPHALARTOS. l.")! 



E. horridus, Lelim. Three or four vascular zones, greatly divided up into distinct 

 segments in places and very irregular in position, are already formed. Tlie pith in the 

 lowest part of the stem is extremely small in area, and traversed by strands running 

 across from one part of the cylinder to the other. Higher up in the stem only two 

 vascular zones are present ; the origin of the second one, from cambial divisions taking 

 place in the parenchyma 8 or 10 layers of cells away from the first zone, is very clearly 

 seen in the uppermost part of the stem. 



Medullary Ijundles and mucilage-canals are very sparse in this plant, at least at this 

 stage of its development. 



A curious concentric grouping of bundles in the cortex was observed in one transverse 

 section from the lower part of the stem, reminding one of a similar case seen in the 

 cortex of the stem of Macrozamia Fraseri, Miq., and of the concentric grouping of the 

 leaf-trace bundles in the Medulloseae. 



In some of the radial sections of the vascular zones the large, reticulate tracheides 

 resembling transfusion- tissue are very clearly recognized amongst the parenchyma- cells 

 between the two zones. 



Structure of the Moot. 



The thick adventitious root has a structure which is, doubtless, quite similar to tliat 

 which the primary tap-root would have presented had it been present. Developed 

 around a small pith are two very thick vascular zones. At one point, immediately on the 

 outer periphery of the second zone, is a thick strand of secondary tissue, curved slightly 

 inwards at each end, similar, although not so far advanced towards the concentric 

 structure, as the large cortical strand described above for E. horridus, Lehm. Thus we 

 find here the same structure as in the transitional region between stem and root in 

 E. horridus, Lehm., with the exception tliat in the latter one vascular zone instead of 

 two is developed. 



The structure of an adventitious branch of E. Altemteinih Lehm., was also examined, 

 but as it reveals nothing fresh, but exhibits essentially the same structure as that of 

 E. ImmginosKS, Lehm., a separate description thereof is not deemed necessary. 



Summary and General Conclusions. 



The following are the chief results, with the conclusions I formulate therefrom, which 

 accrue from the comparative investigation of the above species of Encephalartos :— 



1. The structure of the vegetative organs, consisting of stem, leaf, and root, of the 

 four species of Encephalartos is in almost all respects similar to that of the two species 

 of Macrozumia^ viz., M. Fraseri, Miq., and M. Denisonii, F. MuelL, already mvestigated 



by me. 



The difference in the reproductive organs between the two genera, upon which 

 systematists have hitherto founded their classification, appears to me to consist of quite 



