At the summit of l i the sheath, above the origin of the blade, is the ligule, a usually membranous process of small size (occasionally reaching r in.
Melica uniflora has in addition to the ligule, a green erect tongue-like process, from the line of junction of the edges of the sheath.
Of Danthonia) with the ligule of the developed foliage-leaf.
Some Commelinaceae and Marantaceae approach grasses in foliage; the leaves of Allium, &c., possess a ligule; the habit of some palms reminds one of the bamboos; and Juncaceae and a few Liliaceae possess an inconspicuous scarious perianth.
The simple leaves, which are of small size and do not possess a ligule, are arranged spirally around the branched stem in the majority of the species.
The simple, uni-nerved leaves have a ligule near the base; the base of the ligule is somewhat sharply marked off from the other tissues of the leaf.
In some species a depression of the leaf-surface encloses the ligule, regarding the function of which little is known.
The leaves, which were of simple form and provided with a ligule, were, as the leaf-scars on the stem show, variously arranged.
Each leaf bears a ligule resembling that of Selaginella in structure and position.
The leaves have a single main bundle, and in the mesophyll are four longitudinal series of large intercellular spaces separated by transverse diaphragms. The sporangia, which are situated singly on the adaxial surface of the leaves, between their insertion on the stem and the ligule, arise from a considerable number of epidermal cells.
In the median line, immediately above the leaf-scar, is a print representing the ligule, or rather the pit in which it was seated.
The most interesting point in the structure of the leaf-base is the presence of a ligule, like that of Isoetes or Selaginella, which was seated in a deep pit, opening on the upper surface of the cushion, just above the insertion of the lamina.
A ligule is present immediately ?` `?
The sheaths (Chamaerops), showing the veins ending in a process 1, called running from the base to the mara ligule; the blade of the gin, and not forming an angular leaf, f.