2 



THE NATURALIST. 



be distinguislied by differences so minute and so fugitive, that it would be 

 requisite, before they could be recognised, to study and compare them in the 

 living subject, and oftentimes to examine them when under cultivation. In 

 a dried state it would be almost impossible to determine them. This is the 

 opinion of M. Jordan himself. — " But the study of the Thlaspi from herba- 

 ria is very difficult on account of the variations which the characters drawn 

 from the silicule occasionally present, according to the season and the une- 

 qual development of individuals, particularly in length, the separation of 

 the lobes from the sinus, as well as the length of the style, which is more or 

 less salient according to the state of the sinus.'' ^ Even when under culti- 

 vation, the study of these new species is surrounded with difficulties, witness 

 again the author of the "Diagnoses": — "The leaves of the different species 

 of Eropliila ought always to be examined on young plants, before the appear- 

 ance of the flowers, — in autumn or the end of winter, when they have not 

 suffered from frost. The leaves which remain on the fully developed plant, 

 are generally very little characteristic, either in form or colour." ^ In 

 speaking of the new types, derived from Palaver Rliaeas, he also says : — 

 • " The characters ought always to be studied on individuals which have passed 

 through winter, and which are in a sufficiently normal state, rather luxm^iant 

 than otherwise. In poor plants, the characters do not disappear, but they 

 are less striking, and the characteristic fades of the plant almost entirely 

 fails, which causes the specific form of the plant to be disguised, to those 

 who are not previously familiar with such studies. The same remark may be 

 applied to many other groups somewhat numerous in annual species, as Viola 

 sect. Melanium, Erophila, &c., which should always be studied from the 

 finest individuals, — those in which the development is very complete and 

 normal."^ ° 



Having studied these closely allied forms in the living state and under 

 cultivation, there still remains the difficulty of identifying them. And what 

 labour is required in this identification ! We request all who have sufficient 

 curiosity to search in nature for the species described by M. Jordan. How 

 many have succeeded, after immense labour, in identifying any of these new 

 forms ? Consult any herbarium and you will find that nearly all the forms 

 given with a synonym of M. Jordan have their s2Decific name followed by 

 the sign C?). We cannot be sure of their authenticity unless the master 

 himself has named*them. ^ 



(8) Loc. cit., p. 269. (9) Loc. cit., p. 207. ' 

 (10) Loc. cit., p. 100. 



