538 GRAMINEjE. 



and enclosed within bracts, the whole together forming a locusta 

 or spikelet (figs. 760-762). The outer imbricated bracts are called 

 glumes; they are usually 2 (figs. 760, 761 ge gi], sometimes 1, 

 rarely wanting, and often unequal. They are either awned (aristate) 

 or awnless (muticous). The bracts enclosed within the glumes are 

 called palese or glumella3 ; they immediately enclose the stamens, are 

 usually 2, the lower being simple, and the upper being formed of 

 2 united by their margins (fig. 7Qlpepi). The innermost set of 

 bracts consists of two or three hypogynous scales (squamulae, glumel- 

 Iula3, or lodiculae), which are either distinct or combined (fig. 763 ^>), 

 and are sometimes wanting. Stamens hypogynous, 1-6 or more ; 

 anthers dithecal, versatile (figs. 337, 763 e). Ovary simple (fig. 763 o); 

 ovule ascending, anatropal ; styles 2 (fig. 763) or 3, sometimes united ; 

 stigmas feathery or hairy (fig. 410, 763 ss). Fruit a caryopsis (fig. 

 467). Seed incorporated with the pericarp ; embryo lenticular, lying 

 on one side of farinaceous albumen (fig. 495), near its base (figs. 764, 

 765); endorhizal in germination (fig. 124). Herbaceous plants, with 

 cylindrical, hollow (fig. Ill), and jointed stems, called culms; alternate 

 leaves, with a split sheath and a membranous expansion at the junction- 

 of the petiole and blade, called a ligule (fig. 194), the collections of 

 flowers (locustse) being arranged in spikes, racemes, or panicles. 



Discussions have arisen as to the true nature of the paleas in 

 grasses. Brown thinks that the upper palea is composed of two 

 parts united, while the inferior palea is the third part. The arrange- 

 ment is thus trimerous, and bears a relation to the scales or lodiculse. 

 Mohl on the other hand states, that the inferior palea is not on a 

 level with the other, and is in fact a bract from which the other is 

 developed. From their alternate position, the parts of the flowers 

 of grasses are in general looked upon as bracts, rather than as parts 

 of a true perianth. The following may be given as a general view of 

 the parts of the flower : 



1 . Outer envelope : One or two glumes, the calyx of some authors, containing 



one or more flowers, with distinct insertions on a common axis. When 

 one glume is suppressed it is the exterior or lower. 



2. Inner envelope: One or two palese, corolla of some authors, calyx of Jussieu. 



Inner or upper palea sometimes suppressed. This palea (valve) consists 

 usually of two confluent valves, as shown by two ribs equidistant from the 

 axis. Hence this envelope is, according to some, a ternary perianth. 



3. Squamulse (scales, lodiculse. or glumellulce), occur within the last envelope, 



and at the base of the ovary. 



Grasses are found in all quarters of the globe, and are said to form 

 about ^3 part of known plants. In tropical regions they sometimes 

 assume the appearance of trees. They generally grow in great quantity 

 together, so as to receive the name of social plants. The order has 



