526 



General Botany 



There are 3 50 genera and about 5000 species of grasses. Mostly 

 they are mesophytes, but there are grasses in nearly every habi- 

 tat where plants grow. In size they vary from grasses of 2 or 

 3 inches high to the woody bamboos 60 to 100 feet in height 

 and a foot in diameter. The larger grasses are an important 

 source of building materials, fiber, paper pulp, and in the Oriental 

 tropics of innumerable household articles. 



The spikelet is the unit flower cluster of the grasses. Spikelets 

 may be variously arranged on a single axis, or on highly branched 

 axes, forming spikes, racemes, or panicles. Each spikelet consists 

 of two or more flowers inclosed by bracts, called empty glumes. 

 Each flower is also enveloped by two flowering glumes. Next 

 above are two (rarely three) very small bracts called lodicules, 

 which represent the remnants of a perianth. Next above are 

 three stamens ; and in the center of the flower is the pistfl, made 

 up of three carpels forming a single ovulary with one ovule. 

 It is very evident that the grass flower and inflorescence are 

 highly specialized structures. 



Bureau of Agriculture, P. I. 

 Fig. 329. Japanese cane, a near relative of the sugar cane. It is grown as a fodder crop 

 in the Philippines, and is one of the many useful members of the grass family. 



