182 PLANT ANATOMY. 
larger, hair formations‘ or trichomes* are produced. These 
are found in the most simple, unicellular form, in Stipites Dul- 
camare, on Herba Lobelia and the Chinese galls (Fig. 91), and 
upon cotton-seed (Figs. 92, 114); the root-hairs (Rad. Sarsapa- 
rille, Fig. 126) also belong here. 
The hairs are occasionally very long (flower buds of Althea 
rosea).* Long, sharp, silicified hairs are termed prickles (sting- 
ing hairs of the nettle, Fig. 93 a). Firmer, short, non-secreting 
trichomes are called bristles. Of the latter kind are, among 
others, the hairs of Nua vomica (Fig. 93 b), of anise (Fig. 94). 
The hair formations do not, however, always remain simply 
hair-shaped. Many of them assume other forms (that of a 
star, shield, or head, Fig. 95), throw out branches and become 
Fic. 92.—Hairs of cotton. 
multicellular.* Flatly- expanded multicellular hairs (chaffy 
hairs), such as are of frequent occurrence in ferns (for instance, 
in Aspidium Filix mas) form the so-called Pengawar Djambi. 
If the terminal cell of a multicellular trichome becomes ex- 
‘Compare Weiss, ‘‘ Die Pflanzenhaare,” in Nos. iv. and v. of the ‘“‘ Bo- 
tanische Untersuchungen,” of Karsten, 1867. Rauter, loc. cit., 31. Mar- 
tinet, Annal. d, sciences natur., xiv, (1872), 91-282. Paschkis, ‘‘ Pharma- 
cognostische Beitrége.” Zeitschr. d. allg. oesterreich. Apothekervereins, 
1880, Nos. xxvii. and xxviii. Hanstein, Bot. Zeit., 1868, 725. De Bary, 
“* Anatomie,” p. 61, where the literature is given to the year 1877. 
* Opt?, rpryos hair. 
*Sachs, “‘ Lehrbuch der Botanik ” (iv.), 101. 
*The unicellular climbing hairs of the hop, reposing upon a multicel- 
lular cushion, are not of this kind, 
