2 3 ° Jeffrey and Torrey. — Transitional Herbaceous Dicotyledons. 
of the leaves. Our critics’ figure of Abutilon is of indifferent quality, but is 
clear enough to show that it does not represent conditions in the nodal 
regions of the stem, and as a consequence has no bearing whatever on this 
discussion. 
Turning our attention to the genus Hibiscus , illustrated by their Fig. 8, 
PI. XXXIX, it is clear that foliar rays are present even in their indistinct 
and technically inadequate figure. In view of that fact it is surprising 
that they should deny the existence of foliar rays in the genus Hibiscus. 
In our Fig. 9, PL XI, is shown a total view of a three-year-old stem of the 
genus under discussion. On the right can be distinctly seen a foliar ray 
related to a corresponding trace and extending through three annual rings. 
Fig. 10, PI. XI, shows a part of the leaf-ray more highly magnified. It is 
distinctly a structure differentiated from the normal organization of the wood 
by crowding of the ordinary rays and by the absence of vessels. The leaf- 
ray of Hibiscus is in fact a typical aggregate ray consisting of crowded wood 
rays separated from one another by fibrous bands, which include no vascular 
elements. The fibres contained in the aggregate leaf-ray of the genus under 
discussion represent a more primitive condition than that found in Abutilon , 
since the ray is here still in the aggregate condition throughout and has not, 
as in the case of the latter genus, been largely transformed into the homo- 
geneous compound type of foliar ray, by the septation of the separating 
fibrous bands of the aggregation of rays into storage parenchyma. It seems 
clear that neither Abutilon nor Hibiscus justifies the sweeping statement of 
our critics as to the absence of foliar rays in the aerial stems of herbs of 
Malvaceous affinities. It is rather surprising that our authors did not have 
recourse to such common types as the Hollyhock [Althaea) and the various 
Mallows to support their assertions. An examination of these forms 
reveals a complete agreement with the data illustrated in our figures of 
Abutilon and Hibiscus. Among more exotic genera showing the same condi- 
tions as regards foliar rays may be mentioned Sid a, Napaea , Abelmoschus , 
Gossypium , Lavatera , &c., &c. In concluding the statement regarding 
herbaceous representatives of the Malvales, we may appropriately reiterate 
that the aerial stems of these are distinguished from arboreal forms of 
similar systematic affinities by the development of distinct foliar rays in 
relation to the entering foliar traces. Other things being equal, these are 
the better developed the more advanced in the herbaceous scale are the 
plants under examination. 
Before leaving the Malvales it will be well to devote some attention to 
the nature of the leaf-gap, since there is obviously some confusion in certain 
quarters on this subject. Fig. 7, PL XI, shows a part of the woody cylinder 
of a year-old stem of Tilia at the level where the foliar trace is beginning to 
enter the stem. Internal to the trace, which appears as a black area, is 
a radially directed mass of parenchyma ending in the pith. This is the 
