Se ee PIÓ 
FRUIT OF MELOCANNA BAMBUSOIDES. 423 
carp (to some extent the physiological equivalent of the endosperm of the typical grass 
seed) and the haustorial epithel of the scutellum. In this way, we may imagine, the 
Melocanna seed has become endospermless or “ ex-albuminous.” With the growth of 
the rudimentary ovule, as a distinct entity within the fruit, soon ceasing, the embryo- 
sac develops outside the ovarial cavity in the body of the ovary. It retains, however, 
only the scutellum, whilst plumule and radicle at an early stage burst its bonds and 
push their way to the fruit-base. Thus we have in Melocanna a case where deep-going 
structural modifications and a corresponding transference of functions have taken place 
in the evolution of a most essential organ, otherwise so uniform in the order, with the 
result of securing under very different conditions that complete harmony in the economy 
of the organism which is the fundament of its existence. 
It will be asked what light the structure of the Welocanna seed throws on that much 
. discussed question of the morphological value of the scutellum, the coleoptile, and the 
epiblast. Highly specialized types, like MWelocanna, rarely help us in the elucidation of 
obscure homologies. In this case, it is true, the differentiation of the embryo was little 
affected by the great modifications which the Melocanna fruit has undergone; but if they 
have not obscured or suppressed any of the essential features of the grass embryo, they 
have also not brought to light new traits either to confirm or to refute Schlickum’s and 
Goebel’s conception of the grass embryo, which, to my mind, is the only one that is 
really rational if we insist on reducing the monocotyledonous embryo to one definite 
type. 
EXPLANATION OF THE PLATES. 
PLATE 45. 
to 
1. Mature fruit, seen in the position as it hangs on the tree: e£.—embryotegium.  (j5. 
2. Mature fruit, side view: /r.—lateral ridge ; vr.— ventral ridge. (,°5-) 
3. The same, in longitudinal section: p. — pericarp; d.-— diaphragm; $c. —scutellum ; e£. —embryo- 
tegium ; pl.=plumule; r.=radicle. (g) ` 
4. Mature fruit, from below : pa.— palea; va.— valve; rh.=rhachilla (fruit-stalk). (Lë 
5. The same, in cross-section : letters as in fig. 3. (;°-) 
6. Germinating fruit. (,%-) 
7. The same, in longitudinal section, roots cut: letters as in fig. 3. (By) E 
8. Young hermaphrodite flower, front view: pa.=palea ; l.=lodicule; st.=stamens ; pi. =pistil. 
(4X.) : ids 
9. The same, with the palea and stamens removed, back view: rh.=rhachilla (continuation) : 
l. and pi. as in fig. 8. (4x.) 
10. Mature female flower with barren stamens, no lodicules. (4x .) 
