618 PER- 
and then, in fome way or other, to promote their difper- 
fion. It is curious to obferve how admirably the very 
fame part is contrived to anfwer thefe oppofite intentions. 
This is generally accomplilhed on hygrometrical prin¬ 
ciples. While moift or juicy, the valves remain clofed ; 
but, in drying, they fly or fplit afunder; thus moreover, 
by an elaftic action, aflitling in the difperfion of their con¬ 
tents; and that in a dry ftate of the atmofphere, which 
is molt favourable to the flowing feeds in general. An 
exception to this rule has been obferved in fome annual 
fpecies of Mefembryanthemum, natives of the fandy coun¬ 
try of Africa, where the arid foil but rarely enjoys the be¬ 
nefit of rain. The capfules of thefe expand by means of 
wet alone, when the elaftic valves of each feparate cell 
projeft their feeds to a diftance, to take advantage of a 
favourable moment for vegetation, that might not foon 
occur if they were fent abroad during the dry feafon. 
Juicy pericarps commonly ferve for the food of animals, 
more efpecially birds, in whofe dung their feeds are depo- 
fited, at a diftance from the fpot where they grew, and in 
a condition peculiarly favourable for vegetation. See 
Botany, vol. iii. p. 250. 
PERICAR'PIUM, [from wapwo;, Gr. the wrift.] A me¬ 
dicine applied to the wrift as a charm to cure the ague. 
Sometimes called epicarpium. 
PERICHAs'TIUM, J'. [from the Gr. wsp», about, and 
Xcidvi, a hair or brittle.] A fcaly (heath peculiar to modes, 
which owes its name to its fituation around the bafe of 
their briftle-like fruit-ftalk. It belongs alfoto the male, 
( or barren, flowers of thefe plants, and indeed conftitutes 
their calyx in both flexes. The perichaetium confifts of 
feveral imbricated leaves, differing, in a more or lefs lin¬ 
king manner, from the genuine foliage of the plant, 
either in ftrudture, dimenfions, or colour. In Hypnum 
it is of great confequence, conftituting, by its prefence, 
a part of the generic character, and aflifting powerfully, 
by its diverfities of (hape, proportion, orftrudture, in the 
ciifcrimination of fpecies. Its duration is remarkable in 
fome inftances, even to the extent of three or four years, 
long after the feed and its pericarp have difappeared; of 
which we fcarcely know an example among the ge¬ 
nerality of other plants. More frequently it is deciduous, 
after having accomplilhed its original purpofe of protec¬ 
tion to the tender organs which it enclofes. See Peri- 
gonium. 
PERICHARE'IA, f [Greek.] A word ufed by the 
ancients to exprefs a ludden furprife of joy, fluch as has 
been frequently known to occalion death. Chambers. 
PERICHON'DRIUM, /. [from tte/u, and car¬ 
tilage.] The inverting membrane of cartilages. 
PERICHORE'SIS, or Circuminces'sion, J\ in theo¬ 
logy, a term employed by the fchoolmen to exprefs the 
exiltence of three divine perfons in one another, in the 
myftery of the Trinity. 
PERICHRPSIS, /’. A word ufed by the ancients for 
a liniment principally of the oleaginous or fpirituous 
kinds, and as thin and fluid as oil. 
PERICLA'SIS, f. [from the Gr. wept, and v.Xacti, to 
break.] In furgery, a fra 61 ure attended with a conlider- 
able wound of the foft parts, and expofure of the bone. 
Chambers. 
PER'ICLES. See the article Greece, vol. viii. 
To PERIC'LITATE, v. n. [ periclitor , Lat. to be in dan¬ 
ger.] To hazard. Cockeram. 
PERICLITA'TION, /. The ftate of being in danger. 
Cockeram. —Trial; experiment. 
PERICLO'SIS, f See Periclasis. 
PERICLYM'ENI FLO'RE. See Spigelia. 
PERICLYM'ENI SIM'ILIS. See Volkameria. 
PERICLYM'ENO ACCE'DENS. See Cinchona and 
Psychotria. 
PERICLYM'ENUM. See Chiococca, Commelina, 
Cornus, Hamelia, Lantana, Lonicera, Loranthus, 
Morinda, and Varronia. 
PER 
PERICLYME'NUS, in the mythology of the poets, 
the brother of Neftor, and one of the Argonauts, wljo 
was fuppofed to have power to transform himfelf into any 
form, and was at laft (hot by Hercules in the (hape of an 
eagle. 
PERI'CO, a town of South America, in the province 
of Tucuman: fifteen miles fouth of St. Salvador de 
Jugui. 
PERICO'NIA, f. [fo named by Tode, from wrpi, about, 
and j£on;, powder; becaufe the fungus is entirely fur- 
rounded, when ripe, with its own dully feeds.] In bo¬ 
tany a genus of the clafs cryptogamia, order fungi.— 
Effential generic charadler. Stalk rigid, Ample, termina¬ 
ting in a. dry_ farinaceous head. There are four fpecies. 
1. Periconia lichenoides, or lichen periconia. This 
proceeds from a black cruft-like bafe, fo as very nearly to 
approach the .nature of fome of the Lichenes ; hence the 
name. It has hitherto been found, only in rainy wea¬ 
ther, among the callings and fweepings of gardens, ad¬ 
hering to (talks of cucurbitaceous plants when old and 
decayed. It is a fummer produ6tion ; and makes its ap¬ 
pearance at the end of June. 
2. Periconia byfl’oides, or flaxy periconia. This varies 
in height between one and two twelfths of an inch 
Magnifying glaffes have enabled us, if we are not egre- 
gioufly miftaken, to difeover a kind of farinaceous dull 
filling up the head, interwoven with many nearly imper¬ 
ceptible fibrous threads, contrived for its internal fup- 
port. This humble clafs of vegetation delights in the 
llubbles and the dead leaves of the greater Carex, or 
(lieer-grafs, (fedge,)and conglomerated ruflies. Itthrives 
moftly in fens and marlhy grounds. The time of its ap¬ 
pearance is April and May. 
3. Periconia flavo-virens, or green-headed periconia. 
A new fpecies, added by Albertini and Sch weiniz. It has 
a (lift, perfiftent, and ftriated, (talk, of a dark-brown co¬ 
lour; the head loofe, farinaceous, with a few filaments 
or fibres, yellowilh-green, and foon vanifhing. In habits, 
fize, and general form, it is fomewhat fimilar to the pre¬ 
ceding fpecies; from which, however, it differs materi¬ 
ally by its head, refembling the Ifaria (which genus it 
manifeftly approaches,) full of farinaceous dull, clearly 
interfperled with fibres, and which, being thrown out, 
appears confpicuoully fcattered upon the ftem, which, 
thickening at the bottom, feems to reft upon a final! 
bulb. In fome the head is oblong, and fomewhat fmooth; 
in others nearly fpherical; of a yellowilh-green tint, 
not unlike the calycian bran;) and, having loft its farina, 
difappearing entirely. We find this gregarious fmall 
fungus upon the damp and half-putrid leaves of the Sor- 
bus aucuparia. Its feafon is the middle of May. It is 
reprefented on the annexed Plate, of the natural fize, 
and lying on a dead leaf, at fig. 1. and conliderably mag¬ 
nified at fig. 2. 
4.. Periconia ftemonitis. Of this there are two varie¬ 
ties : a, common ; C, dwarfilh. The firft variety is ealily 
met with upon the fmall twigs of the goofeberry-tree, See. 
as well as on the wood of the poplar. It appears in au¬ 
tumn, and again in the fpring. The fecond is a micro- 
fcopical plant, about the 24-th part of an inch in dimen¬ 
fions; with a black (talk; the head full of a bran-like 
duft, alh-coloured, intermixed with hairs, like the Ifaria. 
It is gregarious, and often found in the fmall cavities of 
deal-wood, flawed out for ufe. January produces this 
fpecies. Confpettus Fungorum e Methodo Perfooniana. 
PERICRA'NIUM, f. [from the Gr. cnpi, about, and 
xpxn or, the flcull.] The membrane that covers the Ikull: 
it is a very thin and nervous membrane of an exquifite 
fenfe. A fimilar membrane covers immediately not only 
the cranium, but all the bones of the body, except the 
teeth, for which reafon it is alfo called the periojleum. 
Quincy .—Having divided the pericranium, I flaw a fif- 
(ure running the whole length of the wound. Wifeman's 
Surgery. 
PERIC'- 
