THE GRASS FAMILY, 283 



Gramineae. 



The Geass Family. 



This is perhaps the largest order in the world, and 

 contains some 3150 species of nearly 300 genera in 13 

 tribes, with sub-tribes. South Africa has about 90 

 genera. They are all herbs with the exception of 

 Bamboos, which grow to hundreds of feet in height. 

 The leaves have a " split " sheath. 



The stem is called a culm, as in Sedges. It is 

 usually hollow except at the joints, so as to impart 

 strength ; but the sugar-cane has a solid stem, the pith 

 of which contains the sugar. 



The flowers are very similar throughout the whole 

 order ; so that when one has been thoroughly mastered, 

 it is easy to learn how other genera depart from the 

 typical example. 



Bro'mus. — This is a large genus ; several species are 

 European, and there are six at the Cape. 



In the illustration (Fig. Ill), we have all the 

 important details shown. (1) is a part of a panicle, or 

 loose cluster of spikelets, i.e. " little spikes," of sessile 

 florets on alternate sides of the axis, called a rachis 

 (1, a, a). (2) is a section of the culm, or stem, showing 

 the solid node (a) and the hollow internode. The leaf 

 arises from the node having a sheath " split " down one 

 side, embracing the culm. At the top of the sheath 



