H. F. Wernham. 
156 
!t is in the ovary and fruit that Acanthaceae are most notably 
advanced. There is a strong tendency to reduction in ovule-number, 
and this, we shall see, in probable relation to seed-dispersal; this 
reduction proceeds more or less hand-in-hand with reduction in the 
number of stamens. The bicarpellary ovary, which is almost 
always bilocular, rarely contains more than eight ovules in each 
loculus; and in any case the ovules are never very numerous. In 
the tribe Nelsonieae the number is indefinite, and the ovules are 
arranged in two series. In Ruellieae the number is more or less 
indefinite, but rarely exceeds eight; and there are most commonly 
four stamens with anthers equally bilocular. In the higher members 
of the family, comprising about three-fourths of the total number, 
there are regularly two ovules to each carpel. This latter character 
will be readily distinguished in its significance from the exactly 
similar condition which obtains in the Diovulatae. In the latter 
case the condition is practically fixed, and already laid down in the 
ancestry; in the present case the diovulate forms are closely con¬ 
nected with multiovulate species within the limits of the same 
family. This series of forms reflects a special tendency which has 
seed-dispersal as its ultimate aim. The fruit is nearly always 
capsular, rarely baccate ( Mendoncin ). The capsule is usually short, 
and is loculicidal right to the base; on the strength of this character 
Engler has separated Acanthaceae as a sub-cohort distinct from C 
(see table, p. 152), in which the dehiscence-line barely reaches the 
base of the fruit. The latter usually bursts elastically with some 
violence; and the ejection of the seeds is aided by rigid hooked 
processes ( retinacula ), which may be outgrowths either of the 
funicles or of the placentae. The reduction in ovule-number is 
without doubt correlated with the appearance of these woody 
processes, as will be readily conceived, seeing that each seed is 
associated with a retinaculum ; and the seeds, in correspondence 
with their diminished number, are relatively large, and they are 
often compressed. It need scarcely be pointed out that a few large 
flat seeds may be thrown from a bursting capsule to a greater 
distance than many small rounded ones. 
In view of the several complexities described in the foregoing, 
we are led to regard the Acanthaceae as representing the most 
highly-evolved among the living descendants of the multiovulate 
stock. In a type illustrating the upper limits of advance along the 
different lines indicated above, the large flowers will be borne in a 
more or less condensed inflorescence with conspicuous bracts, the 
