P I S O N I A. 
Count Maurice of Naflau to Brafil as his phyfician, and 
pafl'ed the greateft part of his life in that and other coun¬ 
tries of South America. His “ Hiftoria Naturalis Bra- 
filiae,” was publifhed by John de Laet at Amfterdam in 
164.8, folio. It confifts of four books, in which he treats 
not only of the plants and animals of that country, but 
of the inhabitants. It is confidered as a valuable per¬ 
formance, and was republifhed in 1658, with the addition 
of the work of Bontius De Medecina Indorum. 
PI'SO, f. A weight ufed on the coaft of Guinea. 
PISO'GNE, a tow n of Italy, on the north bank of the 
lake Ifeo. Itisa fmall place; but has a harbour, and 
contains 2000 fouls, who poffefs three iron-foundries, em¬ 
ploy many forges, and carry on a very aflive trade. It 
lies twenty miles north-north-weft of Breccia. Oppen- 
heim’s Account of the Cifalpine Republic, 1798, 
PISOLI'THUS,/. Pea-stone ; in mineralogy, a genus 
of calcareous earth. Generic charafiters—Confifting of 
carbonate of lime, a very fmall portion of fand and of 
oxyde of iron, carbonic acid gas, and w'ater: foft, opake, 
without luftre internally, breaking into fpherical gra¬ 
nulations; of a centrically lamellar texture : found about 
warm fprings. There is but one fpecies, called 
Pifolithus Carolinus, or Carolina pifolite. Found 
near the warm fprings of Carlfbad in Bohemia, in Silefia, 
and in Hungary, in the form of round niaffes, from the 
fize of a pea to that of a walnut, compofed of concentric 
layers, each containing a grain of fand in its centre; 
colour white or yellowifh-white, brownifh, reddifh, or 
yellowifh. 
PISOLI'THUS, f. in botany, a genus of the clafs 
cryptogamia, order fungi. Generic eftential character— 
A common peridium, emerging from the ftalk ; when 
ripe, breaking in various dirtflions; inclofing numerous 
peridiola in a cellular fibrous fubftance. 
We are Indebted to Albertini and Schweinitz for the 
difcovery of this genus. They mention but one fpecies, 
which they thus minutely and elegantly defcribe. 
Pifolithus arenarius. The ftem is from half an inch 
to an inch in length and from one quarter to three 
quarters of an inch in thicknefs; diminifhing as it 
defcends, and abruptly broken at its bafe: it is firmly 
fixed in the earth, into which it fends a few yellow wander¬ 
ing radicles. The colour of the ftem is paler than that of 
part of the fungus, and above it acquires a cellular 
ftrufilure, in which are contained the infant fungelli. 
This part dilates into the common peridium. The latter 
is round, or now and then oval, from one and a half to 
two inches in diameter, and fmooth with the exception 
of fome (light furrows: its rind is thin, opaque, and 
brittle, of a dirty iron-colour, changing to whitifh as 
the fungus decays. Its fubftance is fpongy and fibrous, 
evidently compofed of long filaments : when frefli it has 
a tawney-green hue; and the juice may be expreffed 
from its latticed ftruflure as from a fponge. When 
drying, however, it turns to a black hard mafs which 
very well difplays to our view numerous lamellae cou¬ 
riering the cells. The latter are innumerable; and 
each of them contains a feparate peridiolum, (that is, a 
fmaller peridium,) eafily lqueezed out, and leaving in 
view the empty cell. The peridiola are at firft very 
fmall, foft, and pulpy, and of the fame bright yellow 
colour without and within. In a little time, however, 
they acquire, according to the preffure the cells exert on 
each other, a roundilh or oval form, and their rinds 
(which are cemented to their fubftances by thin 
filaments) become hairy and thin, and difplay only a 
pale yellow colour, while their medulla or inner part 
turns brown, and is fucculent and flefhy. Liftly, the 
whole peridiola turns intoa brown powderintermixed with 
a multitude of threads; each of thefe ftages may often be 
obferved together in a vertical feffion of one plant, the 
top difplaying the peridiola full of the brown dull, the 
middle (hows them large and flefliy, wdiile in the bottom 
and fides they are feen in the firft or pulpy ftate; all 
523 
which is beautifully reprefented, by a vertical fection, on 
the preceding Plate at fig. 8. 
The method of propagation is this: the common 
peridium burfts in various directions, and by its fall 
breaks up the flight connections of the peridiola: their 
duft efcapes, and is carried far and wide. On the high¬ 
road fide, or the borders of the fields, efpecially when the 
foil is fandy and expofed to the fun, thefe fungi are met 
with in abundance from June to November. 
PI'SON, [Heb. extended.] One of the rivers of 
Paradife. Calmet and Reland will have this to be the 
Phafis, which they fay runs northward through Colchis, 
from near the head of the Euphrates, till at laft it falls 
into the Euxine Sea ; but the Phafis, inftead of taking its 
rife near the head of the Euphrates, and running north- 
weft, has its fpring-head about three or four hundred 
miles north of the head of the Euphrates, and runs fouth- 
weft into the Euxine Sea. Bochart and many others 
take Pifon to be the weftern branch of the divided ftream 
of the Tigris and Euphrates, which runs along the fide 
of Havilah in Arabia, and in the beft maps may be feen 
to compafs a confiderable territory. (Gen. ii. 12, 13.) 
Brown's DiB. Bible. 
PISO'NIA, J". [fo named by Plumier, in honour of 
William Pifo ; fee p. 522.] In botany, a genus of the 
clafs polygamia, order dioecia, (heptandria monogynia, 
Swartz,) natural order of nyClagines, JuJ)'. Generic 
characters—I. Male. Calyx : fcarcely any. Corolla : one- 
petalled, bell-fhaped, five-cleft; fegments acute, patulous. 
Stamina: Filaments five, fix, or feven, awl-fhaped ; 
antheras roundifh, twin. Piftillum : germ oblong; 
ftyle fhort; ftigma-pencil ftiaped. II. Female. Calyx 
and corolla as in the male. Piftillum: germ oblong; 
ftyle Ample, cylindrical, longer than the corolla, ereCt; 
ftigmas bifid. Pericarpium : berry oval, often five-cor¬ 
nered, valvelefs, one-celled. Seed Angle, fmooth, oblong. 
—Effential CharuRer. Calyx fcarcely any ; corolla 
bell-fhaped, (funnel-fliaped, Gcertner.) five-cleft ; ftamina 
five or fix; piftillum one; capfule fuperior, one- 
celled, valvelefs, one-feeded. Male and female on 
the fame or on different plants. There are feven fpe¬ 
cies. 
1. Pifonia aculeata, prickly pifonia, orfingrigo: fpines 
axillary, fpreading very much. The male plants of the 
prickly pifonia differ fo much in appearance from the 
female, that thofe who have not feen them rife from the 
fame feeds would fuppofe they were different fpecies. 
The male plants have (talks as thick as a man’s arm, 
which rife ten or twelve feet high; the bark is of a dark 
brown colour, and fmooth ; thefe fend out many 
branches by pairs oppofite, which are much ftronger than 
thofe of the female, and do not hang about lo loofe. 
They are garniflied with obovate ftiff leaves, an inch and 
a half long, and an inch and a quarter broad, (landing 
oppofite on fliort foot-flalks. From the fide of the 
branches come out fhort fpurs, like thofe of the pear- 
tree, having each two pairs of fmall leaves at bottom ; and 
from the top comes out the peduncle, which is (lender, 
about half an inch long, dividing at the top into three; 
each of thefe fullains a fmall corymb of herbaceous yellow- 
flowers, each having five ftamina Handing out beyond the 
petal, terminated by obtufe antherae. 
The ftalks of the female plants, not being fo ftrong as 
thofe of the male, require fupport. Thefe rife eighteen 
or twenty feet high, fending out (lender weak branches 
oppofite, which are armed with fliort ftrong hooked 
fpines, and have fmall oval leaves, about an inch and 
three quarters broad; thefe ftand oppofite on the larger 
branches, but on the fmaller they are alternate, and have 
fhort foot-ftalks. The flowers are produced in fmall 
bunches at the end of the branches, fitting upon the 
germ ; they are fhaped like thofe of the male, but have 
no ftamina ; in the centre is fituated a cylindrical ftyle, 
crowned with five fpreading ftigmas. The germs after¬ 
wards turn to a channelled five-cornered glutinous 
capfule. 
