HORTUS GRAMINEUS WOBURNENSIS. 13 



The apex, or point, is either acute, (acutum), as in Poa trivialis ; 

 or obtuse, as in Poa pratensis. The circumference has four 

 varieties : 



1. Sword-shaped, (ensiforme), an oblong leaf, growing gradually 

 narrower towards the apex, which is pointed. See Festuca 

 cambrica. 



2. Strap-shaped, (lineare), when both sides of a leaf run parallel 

 to each other. See Sesleria c&rulea. 



3. Awl-shaped, (subulatum), a linear leaf, when it is sharp- 

 pointed, as in Poa glauca. 



4. Fringed, (ciliatum), when the edges are set round with long 

 hairs, as in Festuca sylvatica. 



The surface of the leaves varies as follows : 



1. Channelled, (canaliculatum), when the middle rib of the leaf 

 is furrowed, as in Festuca durimcula, (R. leaves.) 



2. Nerved, (nervosum), when the vessels or ribs are strongly 

 marked, and run from the base to the apex, lengthwise, as in 

 Bromus littoreus. , 



3. Bristle-shaped, (setaceum), when the leaves are nearly cylin- 

 drical, resembling swine's bristles, as in Festuca ovina. 



4. Flat, (planum), when the surface of the leaf is even, without 

 any furrows, dots, or raised veins, as in Poafluitans. 



In respect of situation, the leaf varies : 



1. Slanting, (obliquum), when the leaves are in a direction 

 between sloping and horizontal, as in Phleum nodosum. 



2. Horizontal, (horizontal), when the leaves grow nearly hori- 

 zontal, as in Dactylis patens. 



3. Bundled, (fasciculare), when the leaves grow in tufts or 

 bundles, as in Agrostisfascicularis. 



Sheath, (vagina), is the lower part of the leaf, that encloses the 

 straw in the manner of a sheath. 



Sheath-scale, or stipule, (stipula), of grasses, are small mem- 

 branous substances attached to the inner sides of the leaves; 

 they have their origin at the top of the vagina, or the point where 

 the leaf first diverges from the straw. Its varieties are : 



1. Intire, ( Integra), when it has no segments. 



2. Bifid, (bifida), when it is divided at the apex into two parts. 



3. Torn, (lacera), when it appears as if torn on the margin. 



4. Fringed, (ciliata), when the margin is set with short projecting 



hairs. 



