are not considered, because they may have longer ligules, shorter and broader blades than those at the base, and because they are not readily available in closely grazed pastures.
a. The Bud-shoot
The arrangement of the leaves in the bud-shoot, the vernation, is used as the first point in identification. The blades may be either folded (conduplicate) with the margins meeting but not overlapping (Fig. 1A), or rolled lengthwise (convolute) with the' margins overlapping (Fig. 1 B).
FIGURE 1. Vernation types: A-Leaf folded in the bud-shoot.
B-Leaf rolled in the bud-shoot
The conduplicate type usually forms a laterally compressed shoot, elliptical or lenticular in cross-section (Plate I, Fig. 5). In the convolute type the successive leaves are rolled alternately in clockwise and counter-clockwise manner, forming a cylindrical shoot as a rule (Plate I, Fig. 1). There are, however, a few exceptions in this correlation of the vernation and shape of the bud-shoot; for example, Setaria lutescens, Digitaria sanguinalis and Echimochloa crusgalli (Plate I, Fig. 4) possess rolled blades along with flattened shoots, while Danthonia spicata (Plate 1, Fig. 2), Festuca rubra and F. ovina have folded blades and more or less cylindrical shoots.
The nature of the leaves in the bud-shoot provides a fairly natural basis of separation for the grass species. All the species of the genus Poa and the closely related Glyceria fall into the "folded" class, while all those of the genera 1grostis, 1gropyron, Bromus and the tribe Paniceae (Panicum, Setaria, Digitaria and Echinochloa) fall into the "rolled" class. Certain exceptions, however, occur in Lolium and Festuca., which have representatives of both types.
The vernation may be determined easily by cutting the shoot across immediately below the ligule of the outermost leaf and examining the section with a hand lens. It may be determined, however, without sectioning, by an examination of the innermost leaf after stripping off or pulling back the outer leaves from the bud. Neither of these methods may be necessary
