H. F. Wernham. 
158 
group A of Parietales. The Ebenales appear to be more specialized 
in the character of ovule number, although, as we have seen, the 
multiovulate ovary is not rarely represented. 
Lastly, the parietalian tendency to epigyny is reflected in the 
Styracacese and Symplocacese ; and the similarity between the 
floral characters, e.g., of the latter order and of the Loasaceae 
affords a striking illustration of the parallelism between the cohorts. 
The essential difference lies in the one-chambered ovary of the 
higher Parietales, and the progress to this condition seems to be 
the key-note of special evolutionary development within that group. 
This element is wanting in the Ebenales; they may thus represent 
the sympetalous descendants of the plexus typified in the Gutti- 
ferales of Bentham and Hooker—descendants which have, in some 
cases, adopted the tendency to epigyny traceable in other members 
of the ancestral stock. The possible lines of origin of the Ebenales 
from the parietalian stock is roughly indicated in the above diagram 
In conclusion we may summarize the Pentacyclidae as a poly- 
phyletic group originating by the grafting of sympetaly upon at least 
three archichlamydeous stocks, viz .—the geranial, the c.entro- 
spermal, and the parietalian (see diagram, p. 159.) Sympetaly 
appeared moreover, at a relatively early stage in the progression of 
each stock, so that the working of the primary tendency to economy 
is clearly traceable within each cohort of the sympetalous group. The 
polypetaly, or sub-polypetaly, of not a few members of the latter 
afford evidence of its ancestry; while epipetaly of the stamens, 
expressive of a secondary tendency to economy of material following 
upon the formation of a corolla-tube, is observable within each of 
the three cohorts. As regards the higher general adaptations to 
insect visits, conspicuousness is attained chiefly by the clustering of 
relatively small flowers; the clusters, however, are never so dense 
or so specialized as to bear comparison in point of significance with 
those of Umbelliferte or Compositas: zygomorphy is a very rare 
feature. The absence among the Pentacyclidae of these two 
elements,—close aggregation and zygomorphy—coupled with the 
prevalent pleiomery of the androecium and the remnants of poly¬ 
petaly, lead us to regard them as expressive of the first steps taken 
by different archichlamydeous stocks in the direction of sympetaly, 
before their primary tendencies to economy were at all fully 
realized. 
In these circumstances we are not surprised to find isolated 
cases of epigyny or semi-epigyny in Primulales and Ebenales 
