London Horticultural Society (1818)
LXIII. Account of an original Plant of the Moss Rose de Meaux; with Physiological Observations
by
T
HOMAS HARE, Esq. F.L.S. &c. Assistant Secretary.

Read September 3, 1816.

As it appears to have been generally understood, that the Moss Rose de Meaux, which has so recently become an object of attention, was first introduced into this country from FRANCE, the following particulars of an original plant which occurred in the county of Somerset, seem worthy of being recorded.

In a shady and neglected part of a garden, belonging to Mr. PENNY of Taunton, a common Rose de Meaux had for a long time flourished near a common Moss Rose.

Fifteen years ago, a healthy young sucker of this Rose de Meaux, corresponding in all its characters with the parent stock, was accidentally observed to be clothed with moss, in every respect like the common Moss Rose. In the course of successive years, it received due attention from the possessor, who regarded it as an elegant variety, without having any suspicion of its being unique; and as it had excited the admiration of visitors, several were presented with layers, one or more of which, was about six years since transported to Guernsey, where it was highly esteemed. Thus it may be reasonably conjectured, that the plants imported from Paris about three years since, by Messrs. LEE and KENNEDY, and very generally believed to be the first of the kind ever seen in this country, may have been the progeny of those removed from the west of England to Guernsey; since it was stated, that no others than those sold to Messrs. LEE and KENNEDY had been seen in France.

As the Rose de Meaux has never been known to mature seed in this country, it is not to be concluded that the individual plant of Mr. PENNY'S garden received its new character by impregnation from the farina of the common Moss Rose which grew near it; for although it may be alleged that generative organs have been seen in both these Roses, yet they are always too imperfectly developed to admit of the production of seed.

The accession of Moss to the Rose de Meaux, is not more extraordinary than the numerous variations which the genus Rosa at large has experienced by soil, culture, and local situation. I have in many instances observed the offsets of the most double and high-coloured Belladonna, or Maiden's-blush Rose, produce semi-double and almost single Roses, of a pure white; while suckers of the semi-double white, have been known to produce the Belladonna perfectly characterised, and shoots of the common Moss Rose to produce unmossed flowers.

The moss-like excrescence so frequently produced from the nidus of the Cynips Rosae, on the branches of the common Dog Rose, and which has been called the Eglantine Sponge, or Bédéguar, seems to have suggested the idea of some naturalists, that hymenopterous insects, by piercing the epidermis in many places, might promote considerably the mossy character of Roses, which, in their general habits, exhibit nothing of the kind: but the filaments of the Eglantine Sponge are essentially different from the moss, investing those varieties of Rose, which are known to us with that particular appendage.

It has occurred to me, that the moss of Roses may possibly be no other than an altered form of those glandiferous processes, with which their peduncles and calices are furnished; for where resinous matter exists largely, superabundant moisture, as a stimulus, and shade, as a cause of relaxation, may increase the elastic power of a plant throughout; and thus the pores of its exterior coverings more readily allow the egress of that resinous matter which forms so considerable a part of the moss of Roses, each main fibre of which appears to proceed from a pore, subdividing into many fibrillae: or in other words, the glandulae appear, by the new stimulus communicated to them, to form secondary processes, which abounding with resinous exudation constitute the moss of Roses.

In opposition to this idea, it may be remarked that Roses have been frequently known to lose their mossy character, on being removed from an open situation in which they had previously flourished, to a shady one; the moss becoming elongated, and proceeding from a reduced number of pores. But as the same cause often operates to the production of dissimilar effects, I humbly imagine that this circumstance serves to corroborate rather than to invalidate my conjectures.

The stem and branches of the earlier offspring of the Somersetshire Rose, had much more the common character of plants which had grown in the shade, than those which have been imported from France, namely, a more humid and green appearance, as if the gum-resin contained in them, and which is so abundant in the generality of Moss Roses, were more diluted and aqueous.

The moisture which is common to shady situations, may serve so far to increase the volume of natural fluids in ordinary Moss Roses as finally to destroy their mossy investment, by over excitation of the living powers. Their juices are usually viscid, and of medium quantity. To the support of these properties, neither a particularly dry soil nor a high temperature appears favourable.

The climate of England seems more genial than any other, to the healthy growth of Moss Roses; for it is well known, that in the south of Europe, they are neither so successfully cultivated nor maintain so permanently a genuine mossy character, as in this country; and under a tropical sun, they fail altogether. This latter circumstance may probably be accounted for by the fact, that vegetable, like animal bodies, in a state of growth, are endued with an elastic property, ultimately resulting from series of reticulated tubes, the destruction of which, whether partially or wholly, is fatal to the offices of life. The total absence, therefore, of moss on Roses which grow in tropical climates may be occasioned by an insufficient supply of moisture, owing to the violent heats of those regions, promoting a rigidity of fibre, and a consequent prevention of the determination of resinous matter to the surface of the plant.