CHAP. II. 
HAIRS. 
59 
colour, and connected with the cavernous parenchyma of the 
pitcher. Of these more will be said under the head of 
Glands. 
3. Of Hairs. 
Fig, 15. These [fig» 15.) are minute, 
transparent, filiform, acute 
processes, composed of cel- 
lular tissue more or less elon- 
gated, and arranged in a single row. They are found occa- 
sionally upon every part of a plant, even in the cavities of the 
petiole and stem, as in Nymphaea and other aquatic plants. 
In the Cotton Plant (Gossypium herbaceum, &c.) they form 
the substance which envelopes the seeds, and is wrought into 
linen ; in the Cowhage (Mucuna urens and pruriens), it is 
they which produce the itching. In Ferns they are long, en- 
tangled, strangulated filaments. They vary extremely in 
length, density, rigidity, and other particulars ; on which ac- 
count they have received the following names : — 
Down or Pubescence [puhes^ adj. pubescens), when they form 
a short soft stratum, which only partially covers the cuticle, 
as in Geranium molle. 
Hairiness {hirsuties^ adj. hirsutus)^ when they are rather 
longer and more rigid, as in Galeopsis Tetrahit. 
Pilosity pilosus)^ when they are long, soft, and erect, 
as in Dane us Carota. 
Villosity (adj. villosus), when they are very long, very soft, 
erect, and straight, as in Epilobium hirsutum. Crini (adj. 
crinitus) are this variety in excess. 
Velvet [velumen, adj. velutinus), when they are short, very 
dense and soft, but rather rigid, and forming a surface like 
velvet, as in many Lasiandras. 
Tomentum (adj. tomentosus), when they are entangled, and 
close pressed to the stem, as in Geranium rotundifolium. 
Cilice (adj. ciliatus)^ when long, and forming a fringe to the 
margin, like an eyelash, as in Sempervivum tectorum. 
