AFFINITIES OF DAVIDIA INVOLUCRATA, 323 
derived from plurilocular ovaries, containing in each loculus, we may suppose, a single 
ovule of the Aralian form. At the same time, the organization and structural detail of 
the inflorescence and flower of Davidia are peculiar, and do not indicate close affinity 
with Nyssa and Alangium. The genus occupies a somewhat isolated position, and may 
be regarded as having evolved along independent lines from the plexus of primitive 
groups which included the ancestral forms of Araliacez, Nyssew, and Alangiew. 
Pr 
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SUMMARY. 
The vascular structure of the hypocotyl varies considerably. 
The inflorescence consists of a number of congenitally-fused, apetalous, multi- 
staminate male flowers: or of male flowers and, in addition, a single obliquely- 
situated, apetalous hermaphrodite flower with epigynous stamens arranged in 
series. The arrangement in series is suggested on account of the vascular 
attachment of as many oppositilocular stamens as there are loculi to the ovarian 
cylinder of bundles. 
. The insertion of the bract-trace takes place above the point of insertion of the 
bracts themselves, and sometimes as high up as the torus. There are, therefore, 
three vascular “bundles” on each side of the axial cylinder in the peduncle 
above the insertion of the bracts. 
The ovules in the multilocular ovary—seven being the mean number of loculi— 
are attached axially, one in each chamber, and unaccompanied by a rudimentary 
ovule: correlated with this the vascular bundle in the raphe is made up of two 
bundles, one from each adjacent septum, joined together, and not of a single 
bundle from an adjacent placenta, as is frequently the case in the Araliaceæ and 
Umbelliferæ. 
. The ovule is of the Aralian type, only more specialized, possessing a single, very 
incomplete integument, which grows up leaving the micropyle on one side or the 
other. : 
The nucellus is of small bulk and comparable to the nucelli of Cornus and Aralia. 
It does not persist. i 
The sporogenous tissue usually gives rise to more than one embryo-sae, of which 
only one develops to any extent. A number of abnormalities occur in the 
number, arrangement, and form of the embryo-sac nuclei. The functional 
embryo-sac of the only fertile ovule observed was perfectly normal. Sterilization 
processes in the Caprifoliacese are accompanied by abnormal nuclear phenomena 
in the embryo-sacs of sterile ovules (Symphoricarpus), and by the presence of a 
multicellular archesporium in the nucelli of incomplete ovules (Viburnum). um 
the Rubiaceæ highly specialized ovules are associated with a multicellu ar 
archesporium. Under the circumstances no primitive significance is attached to 
the condition of the archesporium in Davidia. 
8. After fertilization time, the tissues of the congenitally-fused integument and raphe 
nner meristematic zone including 
3 i differentiate into an i ; 1 
(extra-nucellar tissue) and an outer non-meristematic 
the secretory epithelium (internal epidermis), 
