Gh&p. i.] The Leases and Flower. 7 



veflels for the purpofe of conveying and circulating 

 air and the juices necefTary to their nouri foment. 



In plate I. fig. 3. is a fection of the root of worm- 

 wood, as it appears to the eye ; and fig. 4. is the fame 

 magnified. A. A. the fkin with its veiTcls. B. B. B. 

 the bark. C. C. C. the lymph-ducts of the * bark. 

 The other holes are fmall cells or fap-veffels. 

 D.D.D. parenchymatous infertions from the bark. 

 E. E. E. the rays of the wood, with the air-veffeis, 

 This root has no pith. 



III. The leaves are organs eflential to the exiftence 

 of plants. Trees perifh when totally diverted of 

 them j and in general, when llript of any confiderablc 

 proportion of their leaves, they do not moot vigo- 

 roufly. The leaves are formed by the expanfion of 

 the vefTels of the ftalk into a net-work, which exhibits 

 a beautiful appearance when the intermediate paren-* 

 chymatous matter is confumed by putrefaction. Both 

 furfaces of the leaf are covered with a membrane, 

 which is a thin bark, continued from the fcarf-fkin ojf 

 the ftalk. 



IV. The flower con fi (Is of four parts, the calyx, the 

 corolla, the ftamina, and the piftilium. The calyx or 

 flower-cupjsalmoft always of a green colour, and is that 

 which furrounds and fupports all the other parts of the 

 flower. The corolla is of various colours, is varioufly 

 fhaped in different vegetables, and is that which con- 

 ftitutes the moft confpicuous part of the flower. Ic 

 fometimes confifts of one continued fubftance, but more 

 frequently of feveral portions, which are called petals. 

 The ftamina are fuppofed to be the male part of the 

 flower. Linnseus defines them to be an entrail of the 

 plant, defigned for the preparation of the pollen. .Each 

 ftameri confifts of two parts ; the filimentum or fine thread 

 which fupports the anthera, and the anthera or head 



B 4 itfelf, 



