AND ANATOMY OF THE GENUS RESTIO. 215 
have no great value in the discrimination of species. The same 
remark applies, though to a less extent, to the direetion of the 
branches, whether erect or more or less spreading, &e. 
Foliage.—The leaves in these plants: are for the most part re- 
duced merely to the sheath, with a mere rudiment of a stalk or 
blade, but as they vary in form with the different parts of the 
culm, it is necessary to speak of them according to their position. 
The base of the culms is always invested by a number of closely 
imbricated leaf-sheaths (cataphyllary leaves*). These are usually 
of a dark colour and an elliptic form, with a mucro or awn pro- 
jecting from their dorsal surface, just below the apex, almost 
exactly as in Juncus. These scales always closely invest the 
base of the culm, and increase in size from below upwards, 
passing more or less gradually in form and colour to those on 
the middle and upper portion of the culm. The culm-leaves, or 
“vagine ” as they are technically called, are separated one from the 
other by considerable intervals; below they merge into the stock- 
leaves, while above, with more or less abruptness, they merge into 
the bracts or scales of the inflorescence. These sheaths encircle 
the stem, sometimes closely, at other times more loosely: this 
difference, though apparently of little physiological importance, 
furnishes, from its constancy, a good character for the discrimina- 
tion of species, while the disunion of the margins of the sheath 
throughout the whole order is a character of importance as sepa- 
rating its members from the Cyperacee. The form of the upper 
portion of the sheath varies considerably, very generally the mar- 
gins are membranous and more or less hyaline. From the middle 
of the back of the sheath, just below the apex, projects an organ, 
which, according to its form and size, is spoken of as an awn, a 
muero, or even a leaf. In R. graminifolius, Kunth, this so-called 
leaf is more highly developed than in any other species yet met 
with. Morphologically, this portion may be considered to be the 
upper part of the leaf-stalk, assuming that the true leaf-blade is 
absent in these plants as indeed in the majority of Monocotyledons. 
If this be so, have we not in the membranous apex of the sheath 
the homologue of the “ligula” of Grasses, and similar forma- 
tions? In the culm-sheaths the true nature of the awn or 
mucro is not in general so well shown as in the sheaths of the 
smaller branches, where the awn usually assumes the appear- 
ance of a curved needle-shaped leaf. In these smaller sheaths 
* See Henfrey’s translation of Braun’s ‘ Rejuvenescence, Ray Society, 1853, 
p- 62, &e. 
