l62 



SEEDS, BUDS, BULBS. 



Sect. IX. 2. la^ 



rreatefl part of the bark, feem to lofe their vegetable Hfe at the fame 

 ime, and to coalefce, and form the alburnum, or fap-wood ; but the 

 imbilical veffels belonging to the new buds, which are intermixed 

 vith this alburnum, remain alive; and at the returning fpring ad 



with aftonifh 



D 



O 



defcribed in Sect. Ill 



As the fpring advances, the umbilical vefTels, after having drank up 

 the refervoirs of nutriment, M'hich were depofited about the roots, 

 and having thus nourished and expanded the new leaves, ceafe to a6l; 

 and the alburnum gradually changes into hard wood, called the heart 



no longer poffeffes vegetative life ; and is now 

 ate and fuflain aloft the fwarm of biennial plants, 

 d was probably originally produced for this pur- 



of th 



hich 



only -ufeful to el 



which cover it ; 



pofe in the contefi: of all vegetables for light and 



This inert or 

 heart-wood, is e^ 



iifelefs ftate of the central parts of trees, called th 

 ident from thofe old oaks and willows, which hav 



loft their internal hard wood, and 



become quite hollow, confift 



ly of their bark and alburnum, and yet are furniftied with 



many healthy branch 

 poflefs the properties 



B 



the umbilical vefTels of the alburnum 



f capillary tubes 



f a fp 



fter they 



£1. and ceafe to ad as umbilical veflel 



d thus may 



cafionally attract moifture, or fuffer it to pafs through them raec 

 nicallv : whilft the new bark, which confiils of an intertexture of 



dexes of each bud with their radicles, may 



(ion ally abforb 



m 



(lure from' the capillary vefiels of the alburnum, which may be 



compared to the upper fl 



of th 



^ 



6ting by capillary 



pow 



the 



m 



fture from th 



fo 



mmediately beneath it. 



h 



roots of 



may exhale into the atmofphere, or be imbibed by the 

 getables by the fuperior living power of their absorbent mouth 



Th 



It the vefTels of the alburnum in their living flate poflefs the 



property of conveying the fap-juice, which is propelled upwards in 



the early fpring by the abforbent terminations of the roots, is vifible 



in decorticated oaks ; the branches of which expand their buds, like 



I thofe 



St^ 



the 







P 



P 



he 



arl 



ffof 

 I 



off 

 foil' 



tall 



( 



in c 



fOc 



alb 

 wc 



of 



nai 



c 



th 



ha: 

 trc 



A 



.al 



e: 



P 



« ^4 



