14.] CHAPTER II. SPECIAL MORPHOLOGY OF THE MEMBERS. 



65 



margin only, the member is said to be ciliate. A surface with closely appressed 

 hairs is lepidote ; a member bearing ramenta is ramentaceous. 



The root-hairs demand special notice. Root-hairs are hairs which perform the 

 functions of absorption and attachment ; they are commonly developed on roots, 



E 



FIG. 40. Different forms of hairs. A Branched compound hair (Verbascum). I? b 

 Stinging-hair with basal cushion p ; Ti simple hair (Urtica). C Branched simple hair, seen 

 from the surface; e epidermis (Matthiola). D Scaly compound hair (Hippophae) ; a seen 

 from the surface ; b seen in section ; c central cell ; r radiating cells ; s stalk-cell ; e 

 epidermis. E Ramentum (Asplenium) ; b the point of attachment. 



though not always, for they are absent from the roots of a number of aquatic 

 plants (e.g. Butomus umbellatus, Caltha palustris, Hippuris, Myriophyllum, 

 Menyanthes, Nymphsea, Lemna) ; they may be developed on the thallus, or 

 the thalloid shoot, in the gametophyte of Liverworts and homosporous Vascular 

 Cryptogams ; on the stem, though rarely (e.g. Corallorhiza, Epipogum, Psilotum), 

 V. S. B. F 



