This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
It has been long ago explained by the writer of this, and by Mr. Hoopes in his "Book of Evergreens," that many of the curious forms of Junipers, Arbor-vitae and Retinispora, which are well known to cultivators, are but juvenile conditions of well known species. All these plants change their form under different conditions of vegetative vigor. Now and then an individual retains its juvenile form through life, and continues this form even when increased by cuttings. They are in a sense vegetable imbeciles.
It is surprising that this knowledge travels so slowly in Europe. Our poor little 'Tom Thumb," which we all knew to be but the American Arborvitae, pure and simple, it was insisted by our friends on the continent of Europe must be one of the Japanese Retinisporas, and it figures in their writings to this day as "R. Ellwan-geriana." They are still puzzling over it in Europe, and now, seemingly satisfied, have given the whole set new Latin names. Our Retinispora squarrosa is translated to "Chamaecyparis pisifera squarrosa," which we may note, by the way, will have to be again corrected, as it is a juvenescent of R. obtusa and not of R. pisifera. Our Juniperus ericoides and Widdringtonia ericoides, is pronounced to be Chamaecyparis sphaeroidea ericoides. It may be noted here, that in our thirty years of experience with numerous plants, the writer never saw one plant which "went back," or rather advanced enough to betray its relationship. Another is Biota orientalis decussata; a long list of synonyms is attached to this, among which we recognize only our old friend Biota meldensis. That this is really nothing but Biota orientalis, the Chinese arborvitae, we can confirm through one plant advancing far enough to bear a few cones. Our "Tom Thumb" is to be Thuga occidentalis ericoides.
It is certainly Thuja occidentalis; but what is to become of another Thuja "ericoides," which, also a "juvenile" which grows columnar, "Tom Thumb" or "Ellwangeriana," as our friends prefer to call it, growing nearly globose; or the other two or three with spreading and all sorts of habits, which people pick out now and then out of their seed beds? We would suggest to Mr. Hemsley that the first be called Thuja occidentalis ericoides globosa; the other, Thuja occidentalis ericoides globosa pygmaea; the third, Thuja occidentalis ericoides columnaris; and the one with the darker colored leaves, Thuja occidentalis ericoides columnaris purpur-escens. One of these kinds has been found to be better suited to the far north than the other. This fact may warrant the name of Thuja occidentalis ericoides columnaris purpurascens borealis, a name long enough surely to make the "variety" run into popularity like wild-fire.
But seriously, allowing that a real variation from a normal type should be worthy of a botanical name as a botanical variety, what has a botanist to do with a separate botanical name for what is confessedly but a juvenile form of the same thing'? Indeed, why should garden varieties have botanical names at all? We could never see why the slight variations of trees and shrubs should have botanical names any more than pansies or pumpkins. It really seems to us that this practice does more to prejudice the proper use of botanical names in the multitude than the "hardest" generic or specific name.