288 DECOMPOSITE ORGANS. CHAP, f, 



an epidermis encloses a caudex, that consists of two 

 or more substances, or assemblages of substances, 

 totally heterogeneous in their character. 



The Mass consisting of pulp and interspersed 



jfibre* A very common variety of this mode is 



that in which an epidermis or bark encloses a soft 



and pulpy mass, interspersed with a number of 



longitudinal nerves or fibres, or bundles of fib'res, 



extending from the base to the apex, and disposed 



in a peculiarity of manner characteristic of a tribe 



Asexem- or genus. This mode prevails chiefly in herbaceous 



annuals and annual or biennial plants, and necessarily in- 



v l ves some considerable variety ; the pulp being 

 plants. sometimes solid and sometimes tubular, and the 

 fibres being, in both cases, sometimes scattered and 

 sometimes contiguous, sometimes arranged irre- 

 gularly and sometimes in a determinate order. 

 As in as- 1. The Pulp being solid. If the stipe of Aspi- 

 lilix-mas. dium Filix-mas (PL VIII. Fig. 13.) is taken and 

 divided by a transverse section towards the base, 

 it will be found to consist of an epidermis enclos- 

 ing a solid pulp, and to exhibit upon the sur- 

 face of the section, five circular spots of a darker 

 colour than the rest, arranged in a line forming 

 about three-fourths of the circumference of a circle, 

 and concentric to the circumference of the stipe, 

 These spots are the divided extremities of five 

 bundles of longitudinal nerves, as may be rendered 

 evident by opening up the stem longitudinally, 

 when the several bundles will appear in the form 



