522 Worsdell.—The Morphology of the Monocotyledonous 
the sheath of the first one ; but that the theoretical deductions drawn from 
this fact by Coulter and Land and Miss Farrell cannot in any way be 
accepted. 
The same conclusions may be drawn with regard to the embryo of 
Dioscoreaceae and Commelynaceae (Fig. io) ; it may be regarded as 
exhibiting a progressive feature ; the former order is certainly a very 
Fig. io. a and b. Heteraclitia (Commelynaceae). Outline of young embryo (plumular axis 
completely absent). C. Tinnantia (Commelynaceae). Young embryo. D. Tamus communis 
(Dioscoreaceae). Young embryo. c = cotyledonary lamina; s = sheath ; //= indication of plumule. 
(After Solms-Laubach.) 
specialized one, and as regards the latter it is in several ways more 
specialized than the closely allied order Liliaceae, which is more typical of 
Monocotyledons generally. 
Conclusions. 
1. The sciitellum is the lamina of the cotyledon, corresponding to that 
of the foliage-leaf of the Grass. That part of the cotyledon which corre- 
sponds to the sheath of the foliage-leaf is only present at an early stage of 
development, and later becomes completely obscured. 
2. The coleoptile is part of the cotyledon, viz. that which is represented 
in the foliage-leaf by the ligule ; this is clearly demonstrated by the early 
developmental stages of the embryo. The vascular anatomy and the 
abnormal forking strongly suggest a ligular structure. 
3. The epiblast is part of the cotyledon, corresponding, as deduced 
by means of comparative morphological treatment, to the auricles of the 
base of the lamina of the foliage-leaf in certain Grasses. 
4. The cotyledon of the Grass differs in no essential feature, either as 
regards its development or morphological construction, from that of other 
Monocotyledons. 
5. The mesocotyl , as shown by the above facts with regard to the 
coleoptile, and by its anatomical structure, is the elongated primary 
node. 
6. The position of the cotyledon in all Monocotyledons, as shown 
by the facts of development, there being no epicotyledonary axis present 
