POLYTRICHUM SUBROTUNDUM. DwARF PoLYTRICHUM. 
POLYTRICHUM Linnai. Cryptogamia Musci. 
Calyptra duplex, interior membranacea, l*vis, exterior floccida. 
Rail Syn. Gen. 3. Musci. 
POLYTRICHUM fubrotundum caule fimplici anthera fubrotunda. Hudfon FI. Angl. p. 400. 
MNIUM Polytrichoides calyptra villofa. Lin. Syft. Veget ab. p. 796. Sp. PI. p. 1576. FI. Suecic. p. 385. 
MNIUM calyptra villofa, acaulon, foliis ferratis, capfulis cylindricis eredis. Haller, hjl. n. 1837. 
POLYTRICHUM Aloefolium. Scopoli FI. Carniol. p. 309. n. 1290. 
POLYTRICHUM nanum, capfulis fubrotundis galeritis, aloes folio non ferrato. The dwarf round- 
headed Aloe-leaved Polytrichum, Dillen. Mufc. 428. t. 55 . f. 6. 
POLYTRICHUM nanum capfula cylindrica ereda ; furculis limplicibus, breviffimis, foliis ferrulatis. 
Weis Plant. Cryptogam, p. 173. 
MUSCUS capillaceus minor, calyptra tomentofa. Vaill. paris. 13 1. t. 26.fi. 15. 
ADIANTUM aureum medium, in ericetis proveniens. Vaill. paris. 429. t. 55. f. 7. 
MUSCUS coronatus rigidus minoret humilior capitulis villofis brevioribus. Moris. hifi. %.p. 630. t. y.fi 7. 
POLYTRICHUM minus capfulis fubrotundis, calyptra quafi lacera coronatis. C. G. 221. Raii Syn. 
p. 91. 
RADIX tomentofa. 
CAULIS breviflimus, vix ullus. 
FOLIA brevia, rigida, intus concava, extus convexa, 
acuta, margine minutiflime ferrata, bafi lato 
membranaceo caulem ampledente, ficcata in- 
curvata teretiufcula, fig. 1. 
PEDUNCULI fimplices, unciales, rubicundi, fubdiapha- 
ni, flexuoli, Jig. 3, demum tortuofi, fig. 21. 
CAPSULAE fubrotunda:, fig. 4. 
Fig. 2, Folia per lentem vifa. 
5, Calyptra exterior magn. nat. 
6, Eadem magn. aud. 
7, Eadem inverfa ut Calyptra interior 
appareat. 
9, 9, Calyptra interior in litu naturali. 
10, 10, Eadem auda. 
1 1 , Calyptra interior feparata ab exteriore 
et feorfim exhibita. 
12, Eadem in fitu naturali cum exteriore 
connexa. 
13, Capfula magn. nat. nuda. 
14, Eadem aud. 
15, Eadem ad maturitatem magis accedens. 
16, Operculum. 
17, 17, Cilia:. 
18, 18, 18, Membrana mucronata in fummo cap- 
ful* cui adneduntur cili*. 
19, 19, Cilia: in fedione longitudinali Capful* 
exhibit*. 
20, Receptaculum feminis. 
t ROOT woolly. 
I STALK very fhort, fcarce any. 
$ LEAVES lhort, rigid, hollow within, round with- 
I out, lharply pointed, the edge very finely 
$ ferrated, embracing the ftalk by a broad mem- 
branous bafe ; when dried bending inwards, 
$ and of a roundifh form, fig. 1. 
% FOOT-STALKS fimple, an inch high, reddifh, fome- 
I what tranfparent, crooked, fig. 3, finally 
I twilled, fig. 2 1 . 
¥ CAPSULES roundifh, fig. 4. 
I Fig. 2, The leaves viewed through a magnifier. 
^ 5, The exterior Calyptra of its natural fize. 
I 6, The fame magnified. 
I 7, The fame inverted, that the inner 
¥ Calyptra may appear. 
I 9, 9, The inner Calyptra in its nat. fituation. 
¥ 10, 10, The fame enlarged. 
I 11, The inner Calyptra feparated from the 
^ outer one, and fliewn by itfelf. 
i 12, The fame in its natural fituation, con- 
| neded with the outer one. 
y 13, The Capfule of its nat. fize uncovered. 
14, The fame enlarged. 
* 1 c. The fame approaching; more to maturity 
f , 6, The Cover 
i 17, 17, The Cili*. 
$ 18, 18, 1 3 , A pointed Membrane at the fummit 
I of the Capfule, to which the Ciliae 
I are conneded. 
19, 19, The Cili* fhewn in a longitudinal fec- 
I tion of the Capfule. 
¥ 20, The Receptacle to which the feeds 
¥ are conneded. 
ABOUT two years ago, (1776) on examining the flrudure of the Polytrichum commune , in a very young flate, 
I found one of the heads, (Anthera Linn.) after I had diverted it of its woolly Calyptra, covered with a membra- 
nous fhining fubftance, and which 1 had no fooner feen, than I judged it to be a Calyptra, being fo very fimilar 
to the Calyptra’s of forne Mofles I had juft before been examining; and on a more minute inveftigation, I 
found it to be a real Calyptra, not accidental to the plant then under examination, but occurring in all thofe 
which I, at that time, had an opportunity of difleding ; and afterwards found to be in the dwarf variety of the 
fame fpecies, growing on heaths, and in the prefent plant. 
Thofe who fhall take the pains of inveftigating the flrudure of thefe Mofles, will think it ftrange that a part 
fo very obvious to the naked eye, fhould not have been noticed before; but this is eafily accounted for. 
No one, when he fits down to examine thefe Mofles, conceives a priori, that they have any more than one Ca- 
lyptra ; finding that which is peculiar to this Genus, he refts fatisfied, pulls it off, and proceeds to the examination 
of the remaining parts, not imagining that a membranous Calyptra is clofely conneded by its apex to the woolly 
one, pulled off with, and covered by it, and fcarce difcovered but by totally inverting it : but that this is adually 
the cafe, any one may fatisfy themfelves in the courfe of this and the fucceeding months, February and March. 
This inner Calyptra differs very little from the Calyptra of other Mofles ; at firft it wholly furrounds the unripe 
Capfules, as they increafe in fize it fplits at bottom, and finally becomes very fhort. 
I was the more pleafed with this difcovery, as I conceived hopes it would place the genus Polytnchum in a more 
pleafing and fatisfadory point of view ; and I have accordingly ventured to alter its generic charader as above : by 
this alteration it is brought from the Mniums, among which it is placed by Linnalus and Haller, and arranged 
with the Polytrichums of Dillenius, Hudson, Scopoli, and Weis, to which its habit alone certainly entitles it, 
was it not found to accord with the Polytrichum in the efl'ential charader now difcovered. 
Why nature fhould have been thus careful in covering this genus of plants with a warm additional coat, while many 
of the other Mofles, at the fame time of the year, are thinly clad with a Angle membranous veil, does not appear. 
In the flrudure of the two Calyptra’s, there is amort efl'ential difference ; the outer one being a woolly fubftance clofely 
matted together, without any conneding membranous fubftance ; the inner one conlifting wholly of membrane. 
The plant here figured, is the Polytrichum capfulis fubrotundis of Dillenius, and of which that, with the capitulis 
oblongis, feems to be only a variety growing in warmer and lefs expofed fituations. 
It is by no means an uncommon Mofs on our heaths, and expofed hilly and fandy places about town. It 
throws out its ftalks in November and December , and ripens its Capfules in January and February , 
