ELEMENTARY STRUCTURE. 



47 



the epidermis, may develope horizontally and form a stellate 

 hair, as in the Ivy (Jig. 109), &c. ; or two cells may develope in 

 Fig. 103. Fig. 105. Fig. 106. Fig. 107. 



Fig. 110. 



Fig. 103. Moniliform hair ofVirginian spiderwort {Tradescantia virginica). 



■ Fig. 104. Moniliform hair of Marvel of Peru iJIirabilis Jalapa) . 



Fig. 105. Clavate hairs Fig. 106. Capitate hairs Fig. 107. Hooked 



hairs Fig. 108. Glochidiate or barbed hairs Fig. 109. Stellate 



hair from the Ivy. . Fig. 110. Peltate hair from MaJpighia urens. 



opposite directions from another cell raised above the level of 

 the epidermis, by which a shield-like or peltate hair is formed 

 {fig. 110). Besides the above more ordinary forms of hairs, 

 others also occur, which it is unnecessary to 

 mention. Many of the above forms are also 

 found in simple hairs, as well as in com- 

 pound ones, and the figures are taken in- 

 differently from either. Many hairs have 

 one or more spiral fibres in their interior as 

 those on the seeds of Acanthodium, &c. 

 Such frequently form beautiful microscopic 

 objects {fig. 111). 



When the divisions of a stellate hair are 

 closely connected they form a scale or scurj, 

 which may be considered therefore as a mere Fig. 

 modification of such a hair. A scale may be 

 defined as a flattened, membranous, more or 

 less rounded plate of cellular tissue, attached 

 by its centre, and presenting a more or less irregular margin from 



111. Uairs with 

 spiral fibre in their 

 interior, from tlie 

 skin of the fruit of 

 Salvia Horminum. 



