56

GENEEAL REMARKS ON THE

lope of grasses, it may be observed that the view of itsstructure now given, in reducing its parts to the usualternary division of Monocotyledones, affords an additionalargument for considering it as the real perianthium. Thisargument, however, is not conclusive, for a similar conflu-ence takes place between the two inner lateral bracteae ofthe greater part of Iridese; and with these, in the relativeinsertion of its valves, the proper envelope of grasses maybe supposed much better to accord, than with a genuineperianthium. If, therefore, this inner envelope of grassesbe regarded as consisting merely of bracteae, the real perian-thium of the order must be looked for in those minutescales, which in the greater part of its genera are foundimmediately surrounding the sexual organs.

These scales are in most cases only two in number, andplaced collaterally within the inferior valve of the properenvelope. In their real insertion, however, they alternatewith the valves of this envelope, as is obviously the casein Ehrharta and certain other genera ; and their collateralapproximation may be considered as a tendency to thatconfluence which uniformly exists in the parts composingthe upper valve of the proper envelope, and which takesjjlace also between these two squamae themselves, in somegenera, as Glyceria and Melica. In certain other genera,as Bambusa and Stipa, a third squamula exists, which isplaced opposite the axis of the upper valve of the properenvelope, or, to speak in conformity with the view alreadytaken of the structure of this valve, opposite to the junctionof its two component parts. With these squamae the sta-mina in triandrous grasses alternate, and they are conse-quently opposite to the parts of the proper envelope ; thatis, one stamen is opposed to the axis of its lower or outervalve, and the two others are placed opposite to the twonerves of the upper valve. Hence, if the inner envelope be682: considered as consisting of bracteae and the hypogynoussquamae as forming the perianthium, it seems to follow,from the relation these parts have to the axis of inflorescencethat the outer series of this perianthium is wanting, whileits corresponding stamina exist, and that the whole or part