i7ito Natural Groups, Alliances, and Races. 459 



an affinity." It appears from his remarks, that neighbourhood 

 is constituted by the condition of a continuous connexion of 

 I'elation of one species of plant, or group of species of plants, 

 with others. " A group is a collection of families having an 

 affinity." Sir E. F. Bromhead's group seems identical in rank 

 with Dr. Lindley's alliance. (See Gard. Mag., p. 37.) " An 

 alliance consists of a circulating series of groups." The alliance 

 of Sir E. F. Bromhead seems to be identical in rank with the 

 group of Dr. Lindiey. " The two great botanical divisions are 

 named the chenopodeous and thymelaeous races." It may here 

 be a fit place to state, that, in the scheme of arrangement pre- 

 sented, the natural families {orders and suborders, but mainly 

 the former) are assorted upon two opposite pages, each family 

 under the race, the alliance, and the group to which it is deemed 

 to belong; and, if one has understood right, each family, group, 

 and alliance in such a position in its own race as to indicate its 

 deemed affinity, and each so opposite to a family, group, or 

 alliance, in the opposite, as to indicate its deemed relation, not 

 affinity, to that family, group, or alliance. There are two other 

 definitions which one would regard as meant in further expla- 

 nation of this part of the scheme ; if one could but understand 

 them ; namely, these : — " The groups and alliances of the two 

 races, in the same numerical order from the initial group, are 

 said to be parallel." " Successions of groups related to other 

 successions, direct or reversed, in the same or separate races, 

 are said to correspond." 



The following matter, quoted, with a slight degree of adapta- 

 tion, from the work in question, may contribute something to 

 elucidate the foregoing ; and, if it do not, may serve, with the 

 foregoing, to have the not useless effiict of showing the reader 

 something of the nature of ideally grouping species of plants 

 according to the measure of similarity in their structure, which 

 is what is attempted to be done in what is called natural classi- 

 fication ; or, at least, the difficulty of doing this. In the series of 

 families, groups, and alliances that are related by affinity (that 

 is, under each race taken separately, as one understands it), all 

 the adjoining families, or groups, or alliances, whichever one be 

 taken, are related to each other : the parallel series is in a great 

 measure limited to the families, or groups, or alliances, parallel, 

 without strikingly extending to the contiguous families, groups, 

 or alliances. A great source of error has been the endeavour to 

 force together all the families which show relation : our course, 

 on the contrary, should be to form groups of families continuously 

 connected, throwing aside those which do not easily come in 

 succession, for future enquiry, as being probably parallel, or of 

 accidental resemblance. The families so thrown aside will often 

 most unexpectedly form themselves into natural groups, after 



