66 



THE GARDENER'S ASSISTANT. 



under another, those pertaining to botany under 

 yet another, the classification, if not perfectly 

 natural, would at any rate be a nearer approach 

 to a natural mode of grouping than is an alpha- 

 betical index. Again, if the words were all 

 classed according to their relationships and 

 derivation, we should have a natural system of 

 classification. Botanists, except for mere pur- 

 poses of reference, now universally endeavour to 

 frame a natural method of classification. Owing, 

 however, to our imperfect materials and to our 

 inadequate knowledge, a perfect natural method 

 does not exist, and is not likely to be framed, 

 although every accession to knowledge contri- 

 butes towards its improvement. An artificial 

 classification is a purely arbitrary one ; a natural 

 classification is, or purports to be, a scheme 

 representative of the genealogical descent of 

 existing plants and of their relationship one 

 to another, a pedigree, in fact, which circum- 

 stances prevent from ever being complete, but 

 the imperfections of which are ever being 

 lessened. 



Thus, starting from an individual plant, let us 

 say a White Lily, it is incontestable that that lily 

 is the lineal descendant from two parent lilies 

 like itself. We may ourselves have been wit- 

 nesses of the fact. That these parents had a 

 similar history is an inference only, but it is one 

 that no one is likely to dispute. All these indi- 

 vidual white lilies constitute a spi ties. A species, 

 then, is a collection of individual plants which 

 we know, or which we have excellent grounds 

 for inferring, have had a common origin. If 

 we take for comparison with the White Lily, the 

 Martagon or Turk's-cap Lily, we can trace a 

 similar sequence, and we have no difficulty in 

 assuming that all the Martagon Lilies have 

 originated from one stock. It is also obvious 

 that all the individual White Lilies differ from 

 all the individual Martagon Lilies, so that we 

 have now two groups of individuals — the one 

 we call White Lilies, the other Martagon Lilies. 

 In other words, the White Lilies constitute one 

 species, the Martagons form another. Observe, 

 we call them both " Lilies ", because, in spite of 

 differences of appearance, they are still so much 

 alike as to induce us to call them by the same 

 name — Lily. In this way we get a notion of a 

 genus as being a group of nearly-allied species, 

 just as a species is a group of most nearly-allied 

 individuals. 



The genus Lilium, comprising the White Lily, 

 the Martagon Lily, and very many others, is 

 obviously like the Tulip. The Tulip genus, in 

 its turn, comprises many species which differ 



one from another as the species of lily do among 

 themselves; and they differ so much from lilies 

 as to justify the ascription of a different name, 

 Tulipa. Lilium and Tulipa are thus two distinct 

 genera. Allium and Scilla are other genera 

 nearly allied to the two before named, and a 

 vast number of others might be cited. A col- 

 lection of such nearly related genera constitutes 

 a natural order or family, in the case cited 

 called Liliacece. Orders in their turn are grouped 

 in higher divisions called sub-classes, these into 

 higher and larger groups called classes, and so 

 forth. The general principle upon which all 

 these groups are founded is identical throughout, 

 being dependent on the degree of likeness, and 

 therefore of presumptive relationship, between 

 the several members and groups. 



No more common mistake is made in garden- 

 ing books than that of the loose and inconsistent 

 way in which the words variety, kind, species, 

 tribe, family, and so on are employed. These 

 words have in botany a definite significance, and 

 to confuse them, as is generally done, is every 

 whit as inconvenient as it would be to use with 

 equal want of discrimination the words conti- 

 nents, islands, provinces, counties, cities, or other 

 geographical expressions. Each of these has a 

 definite meaning, and one cannot be correctly 

 used as the substitute for another. So it is 

 with botanical arrangements. It may therefore 

 be convenient to insert in this place the principal 

 groups in the order of sequence usually adopted. 



Individual Plant. 

 Variety. 

 Species. 

 Genus. 

 Tribe. 



Order or Family. 

 Cohort. 

 Class. 



Division. 



Minor subdivisions are frequently employed, 

 such as subspecies, sections, subgenera, subtribes, 

 suborders, subclasses, &c, but these require no 

 explanation. In the case of the lilies above 

 mentioned, it may be said that they belong to 

 the Division Phanerogams or flowering plants; 

 to the Class Monocotyledons, inclusive of all 

 plants whose embryo has but a single cotyledon; 

 to the Cohort Liliales; to the Order Liliaceae; 

 to the Tribe Tulipese; to the Genus Lilium; 

 the tw T o Species mentioned being Lilium candi- 

 dum and Lilium Martagon. 



In practice it is in general only necessary to 

 speak of the plant under its generic and under 

 its specific name, thus, Lilium candidum or Lilium 



