THE STEM. 



17 



pubescent (c. pubescens), when it is covered with more or less appressed short hairs 

 (Henbane) ; woolly (c. lanatus), when the hairs are long, close, appressed, and curly 

 (Thistle) ; tomentose (c. tomentosus), when the hairs are short, soft, and matted 

 (Mullein) ;villous (c. villosus), when the hairs are long, soft, and close-set (Forget- 

 me-not) ; hirsute (c. hirsutus), when it bears straight, stiff hairs (Borage) ; hispid 

 (c. hispidus), when the hairs are straight, stiff and very long (Poppy). The ana- 

 tomical structure of hairs will be described hereafter. 



The stem is prickly (c. aculeatus), when the hairs which clothe it thicken, 

 harden, and end in a sharp point; the prickles (aculei) always belong to the 

 epidermis, and come away with it (Rose, fig. 50) ; it is spinous (c. spinosus), when 

 the woody tissue of the stem is elongated into a hard point. Spines (spines) are 

 usually partially developed or arrested branches (Blackthorn, fig. 51), which, under 

 favourable circumstances, produce leaves and shoots. 



The stem is erect (c. erectus), when 

 vertical (Stock, fig. 1) ;~ procumbent or 

 prostrate (c. procumbens, prostratus), I V\ 



when, too weak to support itself, it trails 



60. Rose. Stem with prickles. 



51 1 Blackthorn. 



52.- Bindweed. Twining stem. 



53. Hop. Twining stem. 



along the ground (Knot-grass) ; spreading (c. patulus), when many branches start 

 from the neck, and spread on all sides horizontally (Pimpernel) ; ascending 

 (c. ascendens), when, after being horizontal or oblique at its commencement, its tip 

 becomes upright (Speedwell) ;-^-creeping (c. repens), when a prostrate stem gives off 

 adventitious roots from the nodes (Strawberry, fig. 37) ; scandent (c. scandens), 

 when it raises itself by aid of neighbouring bodies, and attaches itself to them, 

 either by props (Ivy, fig. 47), suckers (Cuscuta, fig. 48), or tendrils (Vine, fig. 130 j 

 Melon, fig. 61) ; the climbing stem is termed twining (c. volubilis)) when it coils 

 spirally round other bodies, rising either from left to right (c. dextrorsum volubilis, 

 Bindweed, fig. 52), or from right to left (c. sinistrorsum volubilis, Hop, fig. 53) of 

 the spectator placed opposite its convexity. 



The direction of the branches depends on that of the leaves from the axils of 

 which they spring; and they are alternate (r. alterni, Rose), opposite (r. oppositi, 

 Valerian), or whorled (r. verticillati, Pine). 







