OOF Se SEL S ST Le ee = ee 
= 
AFFINITIES OF DAVIDIA INVOLUCRATA. 307 
and the yellow ones of Garrya, which are almost completely lignified. The xylem 
consists of vessels, wood prosenchyma, and parenchyma, The degree of lignification of 
the two last-named elements corresponds roughly to that of the phloem prosenchyma. 
In Davidia the fibres are marked with oblique, often highly inclined, slit pits, which 
run in a spiral round the wall and are the cause of a curious optical effect resulting 
from the superposition of fibre walls (series of crosses). Pits with faint borders and 
with circular or elliptic apertures were observed.  Sertoriuss statement* that the 
prosenchyma is marked with bordered pits only (nur Hoftüpfel) is incorrect. The 
sculpturing of the vessel is scalariform or there are multiseriate rows of slit pits or of 
slit pits with faint borders arranged in a spiral. 
2. MORPHOLOGY OF THE INFLORESCENCE AND FLOWER, 
The mature, polygamous inflorescence is a striking object. The flowers form a 
globular head. Inserted some little distance below the head are two large, almost 
opposite, white, sessile bracts, which, spreading from the stem, may reach a length of 
six or more inches. The inflorescence consists either of a number of stamens alone or 
of a number of stamens and a single obliquely situated hermaphrodite flower, the latter 
being on the side of the upper, generally larger bract. Three kinds of flowers were 
originally described, but those described as female may have been hermaphrodite flowers 
bereft of their stamens. The stamens are some five or six hundred in number and are, 
before maturity, seated in tiny foveoli. By subsequent toral growth, the depressions 
become elevations, so that the groups appear minutely pedicellate. The stamens 
emerge in irregular circles and ellipses in any number from one to about twelve, the 
greater number in groups of five or six. They are without a trace of perianth or 
anything equivalent to that structure. The mature hermaphrodite flower is obscurely 
pedicellate, appearing sessile on the torus. It is always obliquely seated. Disregarding 
the stamens, its symmetry is zygomorphie, and it is so in very early stages owing to 
one-sided development. The style arches towards the less developed side. The shape of 
the inferior portion when very young is obliquely hemispherical, tapering towards the 
somewhat cylindrical, curved style. By subsequent growth the ovary becomes ellipsoidal 
(Pl. 31. figs. 7, 8, 9). The plane of zygomorphie symmetry through the ovary may 
coincide with a vertical plane through the axis of the inflorescence or P may Be in an 
oblique tangential plane. The deviation from the vertical is from 30 to 45° The- 
epigynous stamens vary in number from fifteen to twenty-six, forming a zone at 
the base of the style (Pl. 31. fig. 2). The stamens are not hypogynous, as stated by 
Harms t in his account of the Cornaces in Engler’s systematic work. Baillon Ẹ in his 
original account describes female flowers bearing a subepigynous perianth and herma- 
phrodite flowers similar to female, but with hypogynous stamens within the perianth. 
This description is also found in the ‘ Histoire des Plantes'$. In a footnote in the 
* Sertorius in Bull. Herb. Boiss. i. (1893) p. 635. 
t Harms in Engl. u. Prantl, Nat. Pfl., Teil iii. Abt. 8, pp. 250-270 (1898). 
t Baillon in * Adansonia,’ x. (1871) p. 113. 
$ Baillon, Hist. Pl. vi. p. 271. 
