432 



CONSERVATIVE ORGANS. 



[LECT. vin. 



than those which constitute the rays of the fas- 

 ciculus (see marginal cut). Such 

 is the general structure of the 

 majority of strictly annual stems ; 

 but they vary as far as regards 

 the number of the rays of the 

 s.ap vessels and the situation of the proper vessels. 

 The cells of the bark are, commonly, hexagonal, 

 varying however in size ; and those of the central 

 part oblong, and apparently transversely fur- 

 rowed ; but the transparency of their coats ren- 

 ders it difficult to ascertain whether this furrowed 

 appearance arises from oblong slits, opening from 

 one cell into another, or from elevations perhaps 

 of a glandular nature. In -all the annual roots 

 belonging to herbaceous plants, which secrete a 

 white opaque proper juice, as, for example, the 

 PPP V > P a P aver somniferum, nearly the whole of 

 the cells are oblong, or rather tubular ; and are ar- 

 ranged with great symmetry, 

 in the manner figured at a. (see 

 marginal cut). A few cells 

 very highly magnified are fi- 

 gured at b., chiefly to show the 

 appearance of the lateral fur- 

 rows or transverse slits, which 



in the root of the Gourd, I am disposed to believe that, the 

 simple spiral is rarely, if ever, found in the annual root. 



3 



