Seedling Stricture of Gymnosperms. III. 449 
this feature made at the end of the description of Macrozamia apply equally 
well here. 
A comparison of the above account with that given by Matte and 
Thiessen shows that there is much variation ; our second seedling (Series B) 
most closely conforms with what Thiessen found, but instead of the four 
lateral cotyledonary bundles forming two poles of the root they produced 
four, so that the resulting structure was hexarch instead of tetrarch. In the 
first seedling described above the two poles in the cotyledonary plane were 
formed from the three central bundles of one seed-leaf, and from the two 
corresponding strands of the other ; and the intercotyledonary poles were 
formed, one from the extreme lateral seed-leaf-traces on the one side, and 
from a single lateral bundle on the other. Further, the intercotyledonary 
protoxylem rays of the root-structure were in each example organized at 
a level lower than those in the cotyledonary plane. 
Encephalartos. 
Encephalarlos Altensteinii , Lehm. 
The seeds of this plant are larger than those of Dioon , S tang evict, and 
Macrozamia , and the seedling is much stouter, especially older ones which 
have a thick hypocotyl resembling, in many features, those of some hypo- 
geal species of Araucaria. Different stages are represented in PL XXX ; 
Fig. 8 shows the cotyledons embedded in the prothallus to be of unequal 
size 5/ and it will be noticed that the tip of the longer one is wrapped around 
the apex of the shorter ; Fig. 9 indicates the external appearance of a seed- 
ling a little older than the previous one; and, lastly, Fig. 10 represents 
a still older seedling with a thickened hypocotyl. Periderm formation begins 
early, and is indicated in these drawings by the reticulate markings. 
The cotyledons, both as regards their morphology and anatomy, do not 
differ in any feature of importance from those of the plants previously 
considered ; a cotyledonary tube is formed. 
Transition. 
Each cotyledon has five vascular bundles, a central strand bounded on 
each side by a pair of laterals, all of which are much the same in size, 
although, in some examples, the extreme lateral traces may be a little 
smaller than the rest. These bundles travel towards the centre of the 
hypocotyl very gradually, much more slowly than in Dioon and Stangcria , 
and, during this passage, the individual strands of each pair of laterals join 
together so that, when the central region of the axis is reached, there are six 
cotyledonary traces, three derived from each seed-leaf, alternating with the 
bundles from the plumule. Their arrangement is quite regular, the central 
cotyledonary bundles being in the plane of the cotyledons and bounded on 
each side by a lateral. 
