XX. Stigmaria, Sigillaria, &c.--The most remarkable peculiarity of the flora of the carboniferous period is the immense numerical preponderance of the vascular or higher tribes of cryptogamic plants, which amount to two-thirds of the species described. With these are associated a few Palms, Coniferæ, Cycadeæ, and dicotyledonous plants, allied to the _Cacteæ_ and _Euphorbiaceæ_. The number and magnitude of the vegetables bearing an analogy to the _Ductulosæ_, but differing from existing species and genera, constitute therefore the most important botanical feature of the carboniferous flora. Thus we have plants allied to the Equisetum, or mare's-tail (_Calamites_), eighteen inches in circumference, and from thirty to forty feet high; Zamia-like coniferæ (_Sigillariæ_) fifty feet high; and arborescent club-mosses (_Lepidodendra_) attaining an altitude of sixty or seventy feet. Of this ancient flora, the fossil plants whose stems have been named _Sigillaria_ (see Plate XXI.), and their roots Stigmaria, are especially remarkable in consequence of the peculiar circumstances under which upright examples of these trees are occasionally met with. Referring for details to "Wonders of Geology," Lecture VII., I purpose describing in this place the facts recently brought to light, which prove that certain species of Stigmaria are the roots of Sigillariæ; while others in all probability belong to Lepidodendra:--an opinion maintained more than thirty years ago by the Rev. H. Steinhauer.[145] To the late Mr. Binney we are indebted for the first confirmation of the inference of my friend, M. Adolphe Brongniart, (derived from an examination of the structure of those bodies,) that the Stigmariæ are the veritable roots of Sigillariæ. At St. Helen's, near Liverpool, Mr. Binney discovered, in 1844, an upright trunk of a Sigillaria, nine feet high, to which were attached ten roots, several feet long, that extended into the under clay in their natural position;[146] and these roots were unquestionable Stigmariæ, the tubercles with their attached rootlets being clearly displayed. In the floor of the Victoria Mine at Dunkinfold, near Manchester, at the depth of 1,100 feet from the surface, Mr. Binney also discovered a magnificent specimen of Sigillaria, which exhibited on its stem the respective characters of three supposed species, and had stigmaria-roots extending twenty feet. [Footnote 145: Transactions of the American Philosophical Society, New Series, vol. i.] [Footnote 146: See Medals of Creation, vol. i. p. 143.] In the Sydney coal-field at Cape Breton, Mr. Richard Brown has observed several upright stems of Sigillariæ and Lepidodendra, with stigmaria-roots attached; and the same fact has been noticed in the Picton coal, in Nova Scotia. The following figures and notes from Mr. Brown's description of these interesting phenomena, will place the subject before the reader in a clear point of view.[147]