Szabo. — The Development of the Flower of the Dipsacaceae. 329 
and PI. VIII, Fig. 20. The rapid growth of the horseshoe-shaped protuber¬ 
ance begins at its median-posterior part at the flexure, so that the ‘ horse¬ 
shoe ’, which is at first low-lying, rises more and more and the slit becomes 
oblong (PI. VII, Figs. 17, 18). After this follows the growth of the basis 
of the horseshoe, in consequence of which the horseshoe becomes a ring. 
From this ring develops the papillose part of the stigma; the stylar part 
originates in the basal part of the ring. The stigma extends itself and, 
as may be seen in PI. VIII, P'ig. 20, it acts a part as receiver of the pollen 
(/). It is simple, not bifurcated as in the Knautiae. 
Together with the development of the style and its stigma described 
above, the bud also grows in the longitudinal direction and thickens. 
Changes set in also in the ovary-groove. It is thin, resembling a slit 
(PI. VII, Fig. 11). The style (j) with the stigma (V) is situated at the top, 
and in its broader part below there appears a protuberance (< 0 ). This 
protuberance grows rapidly to form the ovule (PI. VII, Fig. 13). The part 
below the junction of the ovule (shaded in PI. VII, P'igs. 9-13) grows just as 
described by Goebel (5) for Valeriana , and by me for the Knautiae (7). 
This part is the part of the axis between the protuberances of the involucel 
(i) and the protuberances of the calyx (k), i.e. the receptacle of the flower 
which finally surrounds the ovary-groove completely. The introrse ovule 
is hanging in the ovary with an anterior suture and a micropyle looping 
backwards and upwards (Baillon, ‘Hist, des plantes’, vii. 1880, p. 520), 
just the opposite to that described by Payer for Dipsacus (see van 
Tieghem (8), p. 185. This situation, however, is not uniform, and it varies 
in accordance with the position of the flower in the inflorescence. The 
longitudinal symmetry-plane of the ovule may decline from the median to 
the transverse direction in a different degree. 
During the further development of the flower (PI. VIII, Figs. 21-9) on 
the development of the cupular ovary follows the development of theinvolucel 
(i). The growth of the calyx (k) is limited. As a general rule in the flowers of 
Dipsacaceae the median-anterior petal-lobe covers the two transversally 
situated lobes and the posterior petal-lobe is covered by the transverse 
lobes. At the time of blossoming, in accordance with the proterandry, the 
stamens are ripe earlier than the pistil, their bent filaments become straight, 
and in the succession the two posterior stamens rise earlier than the two 
anterior ones (PL VIII, P'igs. 25-7). The difference in the behaviour of the 
two anterior stamens is already to be observed at an early period of the 
development; it is probable that the phenomenon is a compensatory one, as 
the cause of it may be the powerful growth of the median-anterior petal-lobe 
which is in connexion with this pair of stamens. On the other hand, the 
retardation of the growth of the median-posterior petal-lobe assists the 
quick development of the two posterior stamens, with which it is in con¬ 
nexion. A considerable elongation of the style takes place after pollination 
