Metaphyta Pteris. 



121 



strands (fig. 49). The parent roots give off lateral rootlets, 

 which spring from cells of the fundamental tissue of the 

 parent root near its apex, and before it has become differen- 

 tiated into the elements of the fibro- vascular bundles. These 

 again give origin to root-hairs like those of the moss. A 

 transverse section of a true root exhibits an appearance not 

 unlike that described for the stem, i.e. externally an epider- 

 mis, which as the root grows older may be replaced by sub- 



FIG. \g. Pteris hastata.-h.VTS.-x. OF ROOT. (Naegeli and Leitgeb.) 



v, apical cell ; c, o, e, tissues of the root ; k, /, m> n, tissue of the root cap. 



epidermal tissue, fundamental tissue traversed by fibre-vas- 

 cular bundles, and with portions of it metamorphosed into 

 sclerenchyma. 



Shoots, The leaves appear on the rhizome as small 

 buds, gradually elongating until they reach the surface of the 

 ground. They are covered by ramenta which protect the 

 young fronds from injury. Each leaf when in the bud has 

 its several parts rolled up in crozier form (fig. 44). The 

 arrangement of leaves in the bud is termed vernation or 

 praefoliation. The leaves of all plants are not arranged in 

 the same manner. Those of the ferns are said to have 

 circinate vernation. 



