32 



EPIDERMAL APPENDAGES — HAIRS, 



occurs, consisting of elongated cells, 

 to which the name of rwmentaceous 

 hairs, or ramenta (ramentum, a shav- 

 ing), has been given. In Palms also 

 a similar substance (but of firmer tex- 



Fig. 88. 



Fig. 87. 



ture) occurs, called reticulum (reticulum, 

 a net), or mattulla, (matta, a mat). 

 Prickles or aculei, as in the Rose, are 

 hardened hairs connected with the 

 epidermis, and differ from spines 

 or thorns, which have a deeper ori- 

 gin. Set(B are bristles or stiff hairs, 

 and the surfaces on which they occur 

 are said to be setose or setaceous. Some 

 hairs, as those of Drosera, or sundew 

 (fig. 88), have one or more spiral fibres 

 in their interior. 



Various names have been given 

 to the different forms of hairs ; they 

 are clavate or cluh-shaped (clava, a club), 

 gradually expanding from the base to 

 their apex ; capitate, having a distinct 

 rounded head ; rough or scabrous, with 

 slight projections on their surface ; 

 ItooJced or uncinate (uncus, a hook), 

 with a hook at ttfeir apex pointing 

 downwards and to one side ; ba/rbed 

 or glochidiate ('y'^c^X'^t ^ barb), with 

 Fig. 87. Scale or scaly hair, from leaf of Hip- 

 pophae rhamnoides. Fig. 88. Drosera dichotoma, 

 double-leaved sundew, showing leaves covered with 

 glandular hairs. The gland is terminal, and there 

 is a spiral fibre inside the stalk supporting the 

 gland. 



