110 



Almost all plants with divided leaves are liable to the same 

 sort of variations ; even those which grow in dry situations. 

 In the IVrns similar appearances are frequently met with. A 

 most striking example is found in the Litobrochia vanenSy 

 PresL, a Brazilian fern, where we have a most decided transi- 

 tion in the form of the frond from lanceolate to trifid or even 

 sagittate. The same tendency to develop itself exists in our 

 Folystichum lohatuMy Roth. Here we have a simple pinnate 

 frond in the variety lonchitidoides gradually running through 

 the ordinary form of P. lobalim until it arrives at the elegant 

 P. aculeatum with its graceful pinnatifid frond. Many botan- 

 ists make three species out of this group, but all express a 

 doubt whether or not they should be considered as varieties of 

 one species, the P. lohatum. 



Another instance of the difficulty in describing the characters 

 taken from the shape or form of the leaves, is afforded in two 

 species of AchillecBf viz., A. tomentosa, Linn., and A. mille- 

 folium, Linn. ; but in this case sufficient to distinguish between 

 the two species is found in the flowers. 



The characters most permanent are those derived from the 

 seed vessel or organs of reproduction. Here we meet with 

 little or no variation. In the PapaveracecB the leaves are so 

 very variable in their form as to preclude our entertaining the 

 hope of ever drawing good specific characters therefrom, but 

 excellent characters may be found both in the shape of the 

 capsule and also in the hairiness of the peduncle. These hairs 

 are either spreading or adpressed to the peduncle; now in 

 both the specimens before us the hairs are adpressed, but dis- 

 tinctive characters are found in the capsule. In Papaver 

 argemone, Linn., the capsule is clavate with erect bristles, while 

 in P. hybridum, Linn., the capsule is ovate with spreading 

 bristles. 



Lepidiwn SniitMi, Hook., is distinguished from £. campesire, 

 R. Br., by the length of the style and the absence of minute 

 scales on the seed vessel. Then again the lovely Erica 



