Transactions of the Linnean Society of London/Volume 1/Observations on Polypodium oreopteris, accompanied with a specimen from Scotland
XIX. Observations on Polypodium Oreopteris, accompanied with a Specimen from Scotland. By Mr. J. Dickson, Fellow of the Linnean Society.
Read January 5, 1790.
THIS plant has been mistaken by all our English botanists. By some it has been confounded with P. Thelypteris, by others with P. Filix mas; but it is very distinct from both. Doody, Dillenius, Ray, Hudson, Lightfoot, Bolton, &c. have all fallen into the same error. For a full account of this plant I beg leave to refer to Vogler, who has written an entire dissertation upon it, and calls it P. montanum. Wildenow gives it the same name. Ehrhart in his Plant. Crypt. Decas 3, No. 22, has published it by that of P. Oreopteris, which we prefer; as the name of P. montanum has been given to another species by Allioni. My opinion respecting this fern is supported by that of Sir Joseph Banks and Mr. Dryander, as well as of Dr. Smith and Mr. Jacquin; and, as the dissertation above alluded to may not be in every body's hands, I shall mention some of the most remarkable particulars in which this plant differs from P. Thelypteris.
1st. P. Thelypt. has a small creeping root, of which see a good figure in Schmeidel's Icones Plant, t. xi. P. Oreopteris has a large scaly root, wrapped and tied together with small strong fibres which cannot be separated without difficulty.
2d. When P. Thelyp. grows old, the under side of the leaf is totally covered with the confluent fructifications, and the edges of the pinnulæ are reflexed or contracted. In P. Oreopt. the fructifications are always on the margins, both in a young and old state, and never run into one another; the lobes oval and plain.
3d. The size of this plant is four times as large as that of P. Thelypteris, and the latter always grows in boggy places; whereas P. Oreopt. grows in dry woods, moors, and on hills, very rarely near water.
Linnæus, in Flo. Suec. says of P. Thelypt. puncta minutissuna dispersa.
I know of no figure of P. Oreopteris. Mr. Bolton has given a small fig. t. 22, f. 2, which may be it; but as he has joined it with P. Thelypt. it is not worth notice[1].
I have found it both in England and Scotland, most plentifully in the latter.
How Mr. Lightfoot could mistake this fern, I cannot understand.
- ↑ Since the above was written, Mr. Bolton has, in a letter to Mr. Dickson, acknowledged his P. Thelypteris to be the P. Oreopteris. His Acrostichum Thelypteris (Fil. Brit. t. 43.) is the true Polypodium Thelypteris of Linnæus.