408 DR. OTTO STAPF ON THE 
IV. GENERAL FEATURES OF THE MATURE FRUIT. 
The mature fruits are ovoid to globose (Pl. 45. figs. 1-7), passing above into a short 
or even obscure, or long and then more or less curved beak. ‘They vary much in size. 
Whilst the smallest which I examined measured 4 by 3:5 cm., the corresponding figures 
of the largest were 12 by 55 em. The weight also varies accordingly from 47 grams to 
180 grams. The fruits are glabrous, smooth or somewhat wrinkled, green, fleshy, but 
hard and tough. Nearly always 3, or sometimes 5, faint, obtuse, longitudinal ribs may 
be observed, one of which descends towards the palea and may therefore be termed 
ventral, whilst the other two are lateral. Opposite to the ventral ridge a shallow and 
often very obscure groove extends towards the base, ending close to the point of 
attachment of the fruit. Here a slight swelling (figs. 1, 3, e¢.), covered by the valve or 
floral glume, indicates the spot where the embryo breaks through the pericarp in the 
course of germination. This embryo spot or embryotegium is, however, by no means so 
distinetly defined as in typical grass fruits, nor is there any trace of a hilum discernible. 
A section in the median plane (Pl. 45. fig. 3) of the fruit reveals the following main 
features of the internal strueture :— 
l. A hard, fleshy, thick pericarp (Pl. 45. figs. 3, 5, 7, p.), of a very homogeneous 
substance, enclosing an oblong cavity, extending from the embryotegium to about 3$ or 3 
of the length of the fruit (exclusive of the beak), and of approximately central position, 
its greatest diameter being equal to about 4 of the diameter of the fruit. 
2. A delicate layer (P1. 45. tigs. 3, 5, 7, d.), lining the cavity and almost indistinguish- 
able to the naked eye, but disceinible under the lens as a fine membrane or in cross- 
section as a fine line of a substance different from that of the pericarp. This layer I 
call the diaphragm. 
3. The embryo, consisting of the embryo proper (Pl. 45. fig. 3, pl. & r.), situated 
close to the embryotegium, and a many times larger fleshy body (figs. 3, 5, 7, sc.), the 
equivalent of the scutellum of the typical grass seed, Kung up more or less completely 
the eavity. 
This very general description discloses already—apart from the great size of the fruit — 
several very remarkable characters which do not occur in the typical grass fruit, viz. 
the powerful development of the pericarp, the absence of endosperm, the corresponding 
enlargement of the scutellum, and the interpolation of a diaphragm film between pericarp 
and scutellum, to which may be added the vivipary, mentioned in the introductory part. 
This deviation from the normal structure of the grass fruit is more or less repeated in the 
fruit of Melocalamus and in a modified form in that of Ochlandra, although the latter is 
not, so far as we know, viviparous. Otherwise it seems to be without a parallel in the 
large order of Graminez, which exhibits so great a uniformity in the structure of the 
fruit. To understand these very singular modifications and their mutual correlation, it 
. is necessary to examine the development of the fruit from the ovary stage and 
its internal morphology in the mature condition. This will be done in the next 
 ehapters. 
