21. I have used the word 'Order' as the name of our widest groups, in preference to 'Class,' because these widest groups will not always include flowers like each other in form, or equal to each other in vegetative rank; {189} but they will be 'Orders,' literally like those of any religious or chivalric association, having some common link rather intellectual than national,--the Charites, for instance, linked by their kindness,--the Oreiades, by their mountain seclusion, as Sisters of Charity or Monks of the Chartreuse, irrespective of ties of relationship. Then beneath these orders will come, what may be rightly called, either as above in Greek derivation, 'Genera,' or in Latin, 'Gentes,' for which, however, I choose the Latin word, because Genus is disagreeably liable to be confused on the ear with 'genius'; but Gens, never; and also 'nomen gentile' is a clearer and better expression than 'nomen generosum,' and I will not coin the barbarous one, 'genericum.' The name of the Gens, (as 'Lucia,') with an attached epithet, as 'Verna,' will, in most cases, be enough to characterize the individual flower; but if farther subdivision be necessary, the third order will be that of Families, indicated by a 'nomen familiare' added in the third place of nomenclature, as Lucia Verna,--Borealis; and no farther subdivision will ever be admitted. I avoid the word 'species'--originally a bad one, and lately vulgarized beyond endurance--altogether. And varieties belonging to narrow localities, or induced by horticulture, may be named as they please by the people living near the spot, or by the gardener who grows them; but will not be acknowledged by Proserpina. Nevertheless, the arbitrary reduction under Ordines, Gentes, and Familiae, {190} is always to be remembered as one of massive practical convenience only; and the more subtle arborescence of the infinitely varying structures may be followed, like a human genealogy, as far as we please, afterwards; when once we have got our common plants clearly arranged and intelligibly named. 22. But now we find ourselves in the presence of a new difficulty, the greatest we have to deal with in the whole matter.