CHAPTEE XII 



CLASSIFICATION OF PLANTS ACCORDING TO THEIR 

 MODE OF GROWTH 



I. Terrestrial Plants, rooted in the Soil. 



The following grouping is based upon the position of 

 the leaves on the stem, and the habit of the stems with 

 regard to light : 



1. Plants with Cauline {i.e., stem or shoot) Leaves only : 



(a) Plants with erect stems. 



(i.) Annual herbs. 



(ii.) Herbaceous perennials, 

 (iii.) Shrubs and bushes, branching freely 



from the ground, 

 (iv.) Trees with trunks. 



(&) Plants with prostrate stems. 



(c) Plants with climbing stems. 



(d) Cushion-plants. 



The Cushion-Plant branches freely at the ground-level, 

 forming a multitude of short erect stems. Most of the 

 leaves are near the extremity of the^stems, the leaves 

 below being smaller and generally wider apart. Such 

 plants may be looked upon as an approximation, through 

 xerophytic conditions, to the rosette-form, by the pulling 

 down to the ground of long-stemmed plants in such a 

 way that the whole plant forms a mosaic of small loose 

 rosettes raised only a few inches above the soil. Many 

 alpines and some maritime plants form these low cushions 

 — e.g., moss -campion (Silene acauUs), mossy saxifrage 

 {Saxifraga hypnoides), sea-purslane (Honckenya peploides), 

 and mountain-avens (Dryas octopetala). 



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