DR. HOOKER ON THE BALANOPHOREuE. 97 



as those may be termed wliicli are founded on the imperfec- 

 tions of organs ; " and he takes the most perfectly developed 

 species as the best exponents of the typical structure of any 

 group, — a principle laid down, we believe, by Mr. Brown. 

 This gives a substantial scientific basis for the estimation of 

 affinity. Agreement in plan of structure is just what consti- 

 tutes affinity ; agreement in grade of evolution may indicate 

 only distant analogy, can indicate only collateral relationship, 

 — not to be neglected, indeed, but in itself of no account 

 in assigning a family to its true position in a system. The 

 principle as aj^plied in the present case leads Dr. Hooker to 

 the conclusion that the nearest relatives of Balanophorem are 

 the Heloragece., a group itself, " consisting for the most i)art 

 of reduced forms of Onagrariem^'' or, more strictly speaking, 

 that the link which connects these plants with the higher 

 forms of vegetation is furnished by Gunnera. The qualifying 

 phrase above is appropriate ; for it is hard to conceive of 

 Gunnera with its minute embryo as a reduced Onagraceay 

 while it is impossible to sever the chain of evidence which 

 binds the genus to Loudonia and Haloragis. Be this as it 

 may, Dr. Hooker has surely made a happy hit in seizing upon 

 Gunnera as the key to the true affinities of Balanophorece, 

 Of all the objections that may be urged against this approxi- 

 mation not the strongest, but rather the least valid, in our 

 opinion (so long as the question is one of alliance and not of 

 co-ordination), is that to be derived from the habit and the 

 imperfection of the foliar organs. Any type is liable to have 

 its parasitic phase, and this is generally a degraded one in 

 these respects ; the Gesneriaceous has it in Orhancheoe^ which 

 it might with the greatest propriety include ; the Scrophula- 

 riaceous graduates insensibly into similar parasitic forms ; the 

 Ericaceous has them in Monotropem ; and the Cornaceous 

 or Olacaceous degrades through Santalaccce into Loran- 

 thacece. 



It is quite probable that our author would deny the degra- 

 dation in the latter case, judging from some points whicli he 

 makes when considering whether the group of Balanophorcce^ 

 '' putting aside any consideration of its relationship with other 



