452 NOMENCLATURE 



define a sp. is impossible. Each man in practice arrives at his own 

 conception somewhere between (or at) the extremes usu. called Lin- 

 nean and Jordanian sp. Draba (Erop/iila) verna for example (Linnean) 

 is distinguished from other D. by absence of petiole and oblong- 

 elliptical pod, but Jordan, studying the sp. in great detail, split it into 

 a great number of forms, to which he gave specific rank, when he 

 found that each one continued to breed true. These were distinguished 

 by "small" characters, such as differences in hairiness, fruit-shape, 

 leaf-form, &c. Cf. Jordan, Diagnoses <?es.peces noiiv. ou me'connues, 

 Paris, 1864, Rosen in Bot. Zeit. 1889, p. 565. 



The most popular conception of sp., and the one used in this book, 

 and in most floras and other botanical books, is the Linnean, or some- 

 where near to it, e.g. as used by Sir J. D. Hooker, or Dr A. Engler. 

 The many forms into which a wide ranging sp. can be divided are 

 classed, the larger and more important as subspecies, the smaller as 

 varieties, subvarieties, and forms. Publication of a sp., by sale or 

 public distribution of printed matter or indelible autographs, consists 

 in the giving of a Latin description of the sp. sufficient to distinguish 

 it from its congeners, and of a name "(Latin or Latinised) by which it 

 may be recognised. The name of the author is then appended (often 

 in abbreviated form, cf. Abbreviations), and publication is complete. 

 A sp. for example may be viscosa (sticky) Jones, or gigas (giant) Klein. 



The next stage above sp. is genus or group of sp., with possible 

 intermediates of subgenus, section and subsection ; and again the 

 difficulty crops up as to the comprehensiveness of the group. What 

 one may consider as a subgenus, or even a section, another may 

 regard as a genus. The great thing is to find a group of sp. clearly 

 marked off by two or three distinct chars, from all other groups. 

 Such a genus as the roses (ftosa), the buttercups (ftanuncultts), the 

 bananas (Musa), the pineapples (Ananas) or the figs (Fiats) is un- 

 mistakeable, and is still defined as it was defined by Tournefort or 

 Linnaeus. But in such a case as Andropogon, Cereus, Eugenia, 

 Loranfhus, Alyristica, Oenothera, the genus is not so clearly marked 

 off, and does not, throughout its members, retain a few well-marked 

 chars, constantly, so that a large number of botanists prefer to split 

 it into other smaller genera. Some of those mentioned are often 

 recognised as composed of 5 to 20 genera. 



Genera are grouped vs\\.o families (e.g. Ranunculaceae), these into 

 orders (e.g. Ranales), classes (e.g. Dicotyledoneae), and divisions (e.g. 

 Siphonogama). But subdivision is usu. necessary here, so that the 

 list of possible headings ultimately runs : 



Div., Subdiv., Class, Subclass, Order, Suborder, Fam. , Subfam., 

 Tribe, Subtribe, Gen., Subgen., Sect., Subsect., Sp., Subsp. , Var., 

 Subvar., Form. 



To every plant is given a binomial appellation, the first half being 

 the gen., the second the sp., e.g. Ranunculus acris. To complete the 

 identification the name of the author of this name must be appended, 

 in this case Linnaeus (L.), as there might be another plant with the 

 same name given by someone else. 



The essential points to aim at are fixity of names, and the avoidance 

 of confusion, but in very many cases these are yet to be arrived at. 



