UPPER {SVPERTERRANEAIS) STEM. 



83 



bark is removed ; as in the tendrils 

 of the Vine 

 (Fig. 101), 

 and .the 

 Spines and 

 Thorns 

 of the 

 Myrrh 

 (Fig. 

 04), the 

 Hawthorn, 

 etc. "When 

 transformed 

 leaves, they 

 come oif 

 with the 

 bark, as in 

 the spines 

 of the Lo- 

 cust, the 

 thorns of 

 the E. o s e, 

 the tendrils 

 of the Cle- 

 matis and 

 Pea. 



Fig. 104.— Myrrh (Bal- 

 samodendron rmjrrha) ; br. 

 with Itb., fls., spines. 



172. Prickles and 

 Hairs belong to the 

 epidermis, or skin, 

 of the bark and leaf. 

 They are often strong 

 and sharp, as in the 

 Teasel (Fig. 105), 

 the Prickly Pear, 

 and Thistle. Hairs 

 are varied in form 

 and texture (Fig. 

 106); they are among 

 the most interesting 

 objects of the mi- 

 croscope ; and they 

 have given rise to 

 most of the poetical 

 terms which describe 

 leaf-surface, as we 

 shall see in Lesson 

 XVIII. 



Fio. 106.— Fuller's 

 fulloniim). 



Teasel {Dipea^us 



Fig, 106. — Hairs of Plants : 1, Delphinium pinnatijidwm, X 

 200diam.; 2, Anchuaa criapa^Y. 200diaiD.; 3, scale-like, from 

 sd. of Cohcea seandens, X 50 diam. ; 4, stellate, If. of Hedera 

 Belix, X 100 diam. ; 5, branched, Yerhascam Thopsus^ X 25 

 diam. ; 6, stellate, Alysmm, X ^^ diam. ; 7, horizontal, 

 stalked, .Grevillea lUhidophylla^ X ^^ diam. ; 8, annulated, 

 from sd. of Buellia formoBa^ in water, X 50 diam. ; 8 a, de- 

 tached cell-wall of same, X 200 diam, ; 9, glandular, Bryonia 

 alba, X 50 diam. ; 10, from sd. of Salvia, X 50 diam. 



