13 
sheath is inserted directly over the scutellum; and, finally, how the 
insertion of the plumule-sheath becomes separated so far from the 
scutellum through the elongation of the axis. He also homologizes the 
grass fruit with Smilax, Potamogeton, Ficus elastica, the mosses, and 
theleaf of the grasses. He regards the seutellum as the blade of the 
cotyledon, and as being homologous with the blade of the leaf. Over 
the scutellum is situated the plumule-sheath which is homologous to 
the ligule. The epiblast is the blade of an opposite second cotyledon, 
SUMMARY. 
The most important views of the different authors may be summed 
up as follows: 
1. The scutellum is the cotyledon; the epiblast a second independent 
leaf; the plumule-sheath a third leaf; while the first true leaf is the 
fourth lateral appendage of the embryo.—(Malphigi, Mirbel, and 
Poiteau.) 
2. The scutellum and the epiblast together form the cotyledon, the 
plumule sheath a second leaf, and the first true leaf becomes the third 
lateral appendage of the embryo.—(Schleiden, Shacht, and Decaisne.) 
3. The plumule-sheath represents the cotyledon, the scutellum and 
epiblast being only expansions of the axis or of the radicle; and the 
first true leaf then becomes the second lateral appendage of the 
embryo.—(Riehard, Adr. de Jussieu, Lestiboudois, Hofmeister, and 
Sachs.) . 
4. The scutellum is the central portion of the cotyledon, the epiblast 
an opposite appendage of it, and the plumule-sheath an ascending part 
in the form of a protective organ; the first true leaf then becomes the 
second lateral appendage of the embryo.—(Gaertner and Mirbel, at a 
certain time.) 
5. The scutellum and the plumule-sheath together represent the 
cotyledon, and correspond to the blade and ligule of the culm-leaf ; the 
epiblast is a protuberance of the cotyledon on the opposite side.—( Van 
Tieghem and Klebs.) 
6. The sixth view is the same as tke fifth, with the exception that 
the epiblast represents a second cotyledon opposite the seutellum.— 
(Celakovsky. 
7. The PS is one cotyledon and the epiblast is the other, the 
plumule-sheath being the first leaf of the plumule.—( Bruns.) 
GENERAL DESCRIPTION OF THE FRUIT. 
The embryo of grasses stands isolated from those of other oen d 
ledons in possessing two peculiar structures, the epiblast and plumu 
Sheath. The followin g investigations were undertaken to — 
the morphological significance and taxonomic value of these 33 
in the different tribes. Owing to the difficulties met with at the out 
