ANATOMY OF THE JULIANIACER. 145 
the involucre ; the latter increases very considerably in size in the fruit, and at the same 
time its cells become thickened in various ways, so that the resulting investment is very 
tough and hard. Each of the flattened ovaries, representing as many flowers, and, as 
will be remembered, adnate to the involucre by their narrow edge along the greater part 
of their length, has relatively thin walls; the latter are, however, of a very hard 
consistency, owing to the occurrence of numerous longitudinal strands of thick-walled 
sclerenchyma in them (Pl. 21. figs. 1 & 2). The strands give the walls a characteristic 
dotted appearance in transverse section, and form the numerous anastomosing ribs on 
the flat sides of the individual ovaries. 
The structure of the young fruit, which was examined in Juliania amplifolia 
(Rose and Hough, 4819), is very different from that of the mature one. Its tissues are 
made up of cells with relatively thin walls, and contain no sclerenchymatous elements 
whatever ; numerous large resin-canals are present, the contents of which are a much 
clearer yellow than in the canals of the vegetative organs. In many points, however, 
the future structure is already indicated. The outer surfaces of the individual ovaries 
at this stage bear numerous multicellular hairs like those occurring on the vegetative 
organs (Pl. 21. fig. 5, #.); the hairs are mostly present in such numbers as to completely 
bridge over the space between two contiguous ovaries. The walls of the ovaries are 
thin in the median region, but broaden considerably as we approach the ends, which are 
connected with the involucre. The external layer of the ovary-wall, bearing the above- 
mentioned hairs, consists of cells which have thin walls and are frequently already at 
this stage considerably compressed, and hence difficult to distinguish ; internal to this 
layer are several layers of thin parenchymatous cells, in which the large resin-canals are 
situated externally, while a limited number of vascular bundles traverse them internally ; 
these bundles run in the transverse plane (Pl. 21. fig. 5, v.b.) The inner lining of the 
ovary-wall is separated from the general tissue of the wall (i. e. that containing the 
resin-canals and vascular strands) by a very characteristic layer of large cells containing 
solitary crystals (Pl. 21, fig. 5, c.L.1). These cells are plano-convex in shape in a 
transverse section, their convex surface being more strongly thickened and facing 
towards the cavity of the ovary. This layer, as will be seen below, is also very easy to 
recognise in the mature fruit, although the crystals contained in it are then of a much 
larger size. The inner limit of the ovary-wall (Pl. 21. fig. 5, ?.ep.) is constituted by 
à layer of cells with slightly thickened walls, and varying very much in size and shape; 
at some points these cells form a single layer, but, as a rule, there are two cells in front of 
one another, In surface-view these cells have a more or less undulated outline. Towards 
the narrow edge of the ovary, where the latter merges into the wall of the involucre,- 
these cells attain a much more extensive development and form a large number of 
layers; at the same time the walls become less strongly thickened, while many of the 
cells are drawn out in various directions, and so become much contorted. At these 
Points, therefore, the inner limit of the ovary-wall, instead of being formed by a definite 
layer, consists of an irregular mass of cells; numerous relatively small solitary crystals 
occur throughout this tissue, being only absent from the innermost cells bordering on 
è ovarial cavity; the latter have somewhat thicker walls, and tend to assume an 
Z 
SECOND SERIES.— BOTANY, VOL. VII. 
