82 



ACADEMIC BOTANY. 



Fig. 102, — Cochineal Cactus (Opttniia 

 eochiniUifera)y with cochineal insects. 



to other plants only in the United 

 States and iii some few localities in 

 England. Climber is a correct term 

 for all scandent stems ; runner, for all 

 that trail or run. 



167. Stems are usually cylindrical ; 

 but in the Sedges they "are triangular 

 (triquetrous) ; in the Mint Order they 

 are square. 



168. Fleshy Stems characterize the 

 Cactus Order. They are usually leaf- 

 less ; the green skin — there is no de- 

 veloped bark — serving the purpose 

 of leaves. In the Prickly Pear (Pig. 

 102) the thick, jointed stems simulate 

 leaves ; the true leaves are minute 

 scales, with bristles in their axils. In 

 the tree cacti the stems are tall and 

 columnar. Other fleshy stems are 

 seen in the Stapelia, the Tortoise- 

 Plant, and some Euphorbias. Growth 

 like this, no matter in what part of the 

 plant it occurs, is called Anomalous 

 (Grr. irregular) , because it departs from 

 established order. 



169. Branches usually spring from 

 buds in the leaf-axils (nodes) of the 

 stem. They are Runners when pros- 

 trate and rooting only at the end, — 

 Strawberry; Suckers when arising 

 from subterranean stems, — Rose, As- 

 pen ; Stolons when they are decum- 

 bent suckers, taking root where they 

 touch the soil, — Gooseberry. 



170. Transformations. — In the 

 Butchers' Broom (Pig. 103), the so- 

 called leaves are branches expanded 

 into leafy shapes, each tiny spiny- 

 tipped ''leaf" bearing a litiile white 

 flower in its centre, which becomes a 

 red berry nearly as large as the leaf. 

 The leaves of the Asparagus and of 

 the "Smilax" (Myrsiphyllum) of the 

 greenhouses are also transformed 

 branches. In all these plants the 

 true leaves are small scales ; they are 

 well seen in young asparagus-shoots 

 Some botanists regard these leaves as 

 transformed peduncles, and term this 

 form of inflorescence Epiphyllous (Gr. epi, upon, phyllon, leaf). 



171. Spines, Thorns, Tendrils, are transformations. When trans- 

 formed branches they are part of the wood, and remain so after the 



Fig. 103. — a. Butchers' Broom (Rus- 

 cua aculeatus) ; 6, fruit ; c, sd. ; d, fl. 



