630 gkaminejE. 



p. 42). — Herbaceous plants, with cylindrical, hollow (fig. 130, p. 64), 

 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. 210, p. 99), the collections of flowers (locustae) 

 being arranged in spikes, racemes, or panicles. 



Discussions have arisen as to the true nature of the palese 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. 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 flowerless or empty glumes, enclosing or suMending 



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 flowering glumes or palese, covering a unisexual 



or tisexual flower. Inner or upper palea sometimes suppressed. This 

 palea (valve) consists usually of two confluent valves, as shown hy two ribs 

 equidistant from the axis. Hence this envelope is, according to some, a ter- 

 nary perianth. 



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



and at the hase of the ovary. These are hy some considered as the true 

 perianth. 



Grasses are found ia aU quarters of the globe, and are said to form 

 about -jV 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 

 been divided into numerous sections, founded on the number of flowers 

 in a spikelet, their hermaphrodite, unisexual, or polygamous nature, 

 the number and form of the different sets of bracts, and the nature of 

 the fruit. Genera, 250 ; species, about 4500. Examples — Oryza, 

 Zea, Phalaris, Panicum, Stipa, Agrostis, Arundo, Echinaria, Chloris, 

 Avena, Bromus, Festuca, Bambusa, Lolium, Triticum, Hordeum, 

 Nardus, Rottboellia, Andropogon, Saecharum. 



This is one of the most important orders in the vegetable king- 

 dom, whether we regard it as supplying food for man or herbage for 

 animals : To the former division belong the nutritious cereal grains, 

 as Wheat, Triticum vulgare, and the varieties spring wheat, F. CBstiwm, 

 and winter wheat, T. hybernum ; Triticum Spelta, spelt, which is DDDS 

 (Kussemeth) of the Bible, translated Rye ; T. compositum, Egyptian or 

 mummy wheat (p. 348) ; Oats, Avena sativa ; Barley, Hordeum vulgare, 

 and its variety H. hexastichum Bere or Bigg ; Eye, Secale cereale ; Bice, 

 Orym sativa; Maize or Indian Com, Zea Mays; Guinea-corn, Sorghum 



