[Illustration: Fig. 8. _Poa trivialis. A_, base of blade. _B_, ligule. _C_, sheath. _D_, culm (× about 3).] [Illustration: Fig. 9. _Alopecurus pratensis. A_, base of blade. _B_, ligule. _C_, sheath. Slightly magnified.] [Illustration: Fig. 10. _Avena flavescens._ Lettering as before (× 2). Note the split sheath, the hairs and ridges. Stebler.] At the junction of the blade with the sheath there is in most cases a delicate membranous upgrowth of the former, more or less appressed to the stem, and called the _Ligule_ (Figs. 8-13). Its use is probably to facilitate the shedding of water which has run down the leaf; and so lessen the danger of rotting between the sheath and stem: possibly the shelves and ears commonly met with at the base of the lamina (Fig. 12) aid in the same process. This ligule may be long or short, acute or obtuse, toothed or entire, or it may be reduced to a mere line, or tuft of hairs, or even be obsolete, and is of considerable value in classification--e.g. the ligule is obsolete or wanting in _Melica_, _Festuca ovina_, _F. Myurus_, _F. elatior_, _Kœleria_ and _Panicum_. It is represented by a tuft of hairs in _Molinia_, _Triodia_ and _Arundo_. [Illustration: Fig. 11. _Lolium perenne. A_, base of lamina, _B_, ligule. _C_, sheath (× 3). Note the low ribs, and absence of hairs (glabrous).] [Illustration: Fig. 12. _Festuca elatior_, var. _pratensis_. _A_, base of lamina. _B_, the extremely short ligule, with pointed ears. _C_, sheath (× 3).] [Illustration: Fig. 13. _Festuca ovina. A_, base of lamina. _B_, ligular ears. _C_, sheath (× about 4). Stebler.] Our other ordinary grasses have a more or less well-developed _membranous_ ligule (Fig. 8). The leaf-blade is long or short, broad or narrow, but always of some elongated form such as linear, linear-lanceolate or linear-acuminate, or subulate, setaceous, &c., varying as to the degree of acuteness of the apex, and the tapering of the base. In the following native grasses the _form_ of the lamina affords a useful character.