CHAPTER XIX 



CLASSIFICATION OF PLANTS 



We have seen in earlier lessons how plants change their forms 

 and habits of growth to suit different conditions of life. 

 Probably none of the familiar plants of the veld look to-day 

 just as they did when they were first created. More than 

 125,000 species or kinds of plants have been described or 

 named, but since differences in soil, the amount of water, or 

 sunlight available now bring about a change in the plants, it is 

 often difficult to say just how many species there are in a 

 district. 



Species are not fixed by absolute characters. Any kind of 

 plant which can reproduce its like by seed, which is fairly con- 

 stant over a considerable territory, and can be described so that 

 it may be distinguished from others, is known as a Species. 



A group of species which are more like each other than 

 they are to other species is called a Genus, or a genus may 

 comprise but a single species if it has a combination of 

 characters not found in any recognized species. 



Just as species are grouped into genera, so genera are 

 grouped into Orders. The many kinds or species of heaths 

 are grouped into the genus Erica. The genus Maaiabia is 

 similar to Erica, but instead of the showy corolla that makes 

 Erica beautiful, the calyx is much longer than the corolla. 

 Other genera may have but four stamens instead of eight, as 

 found in Erica and Macnabia, or the number of seeds may 

 differ. Yet these genera have enough conspicuous characters 

 in common to place them all under the one order EricacecE. 

 These groupings into orders, genera, and species have been 

 made so that we may think and speak of them more easily. 



