11 
scutellum and plumule-sheath together correspond to the cotyledon of 
the other monocotyledons. A. Stephen Wilson! held that the cotyle- 
don of the grasses had not yet been correctly interpreted, and that 
the morphological interpretation lay in whether the two vascular 
bundles of the plumule-sheath represent the middle nerves of two 
leaves or whether they only occur to strengthen the organ. In com- 
paring this with the leaves in the terminal bud of the rhizome of 
Agropyron repens he found a difficulty, owing to the latter being many- 
nerved. He believed that the scutellum certainly has the function of 
a cotyledon and is a nourishing organ for the embryo at germination, 
but whether the plumule-sheath is also a nourishing organ is left in 
doubt. 
Gordon? studied the morphology of the inflorescence. He says that 
the node-like swelling at the base of the plumule-sheath occurs very 
generally in the grasses. It appears to be a part of the node, but in 
reality is only a circular swelling at the base of the closed sheath. 
The proper node lies underneath this swelling. The plumule-sheath 
must exercise a certain pressure on the axis, and if axillary buds are 
present this pressure must have a certain influence on the plumule. 
The author speaks of the well-known organ, which denotes the origin 
of a branch, and which is looked upon by most morphologists as a two- 
keeled simple “ Vorblatt” (prophyllum), with its back turned toward 
the main axis. The axillary shoots in Zea, Tripsacum, Coix, and many 
others make a cavity or groove in the culm, showing that they have 
developed under pressure of the sheath. The tissue at the base of the 
culm remains soft and capable of growth fora long time as » peel 
vegetation point. In other grasses, such as Arundo and Phalaris, the 
axillary shoot does not press itself into the culm. In these the grow- 
ing point breaks through the sheath to the light. In Arundinaria the 
sheath soon dries up and the growing point has nothing to hinder it. 
. Attempting au analogy between the fruit and the spikelet, he con- 
cluded that the plumule-sheath represents two leaves grown together. 
Certain Graminee, he says, have one or two buds in the axil of the 
plumule sheath, each with à prophyllum. 
Warming? regards the scutellum as the cotyledon and the plamale- 
sheath as an independent leaf, the latter because an e is occa- 
sionally found. Klebs* agrees with Van Tieghem. Hackel’ believes, 
as does Warming, that the epiblast is a rudimentary second coty 3 
r d mbryo. Trans. and Proe. of the Bot. 
5 lope of the plumule in the grass-e 
Soc. of Edinburgh. 13:457. 1879 (with plate) — 
Etudes morphologiques sur la famille des Graminees. 
Montpellier. 1879. 
? Handbog i den Systematiske Botanik. Trans. by Potter. ent y Eio 
Beitrage zur Morphologie und Biologie der Keimung. Untersuch aus d. ^ 
Institut der Lubingen. 
5Echte Gräser. Engler und Prantl. 
by Scribner and South worth. 
Revue des Sci. naturelles, 
Pflanzenfamilien, 2:1887. 2. Eng. Trans. 
