dio- it into the borders in November, that the rain 
may wafh down the falts before the fpring comes on ; 
and where the ground is very loofe or Tandy, it will 
be the belt way to make ufe of neats dung, which is 
cooler than that of horfes, but for cold ftrong land the 
latter is to be preferred. 
If the ground is well trenched every year about the 
roots, it will be of great fervice to them •, and where 
the foil is fu 'eject to bind very clofe, if it is forked 
two or three times in a year to loofen the furface, it 
will greatly help the trees. The borders fhould not 
be crouded with any large growing plants, which will 
draw away the nourifhment from the trees 5 therefore 
when any fort of kitchen herbs are planted on thefe 
borders, they fhould be only fuch as are of fmall 
growth, and which may be taken off early in the 
fpring ; and if this is carefully obferved, the culti- 
vating fmall things on thefe borders can do no harm, 
becaufe the ground will be ftirred the pftener, on ac- 
count of thefe fmall crops, than perhaps it would 
have been, when no ufe was to be made of the bor- 
ders. Thefe rules which are here laid down, if pro- 
perly obferved, will direft any curious perfon how to 
have plenty of good fruit, as alfo to preferve the trees 
in vigour a great number of years. 
PER VINCA. See Vinca. 
PETALS are the fine coloured leaves which com- 
pofe the moft confpicuous parts of a flower ; thefe 
are called in Latin Petala, to diftinguifh them from 
the leaves of plants, which are called Folia. 
PETASITES. See Tussilago. 
PETIVERIA. Plum. Nov. Gen. 50. tab. 39. 
Lin. Gen. Plant. 417. Guinea Henweed. 
The Characters are, 
The flower hath a ■permanent empalement , compofed of five 
■narrow obtufle leaves which are equal. It hath flour fmall 
white petals , placed in form of a crofs , which floon fall 
off) and fix awl- fhaped ereht flamina terminated by fingle 
fummits. In the center is fituated an oblong compreffled 
germen , with flour awl-floaped ftyles , crowned by obtufle 
permanent fiigmas. The germen afterward becomes one 
cblong feed , narrow at the bottom and taper, but broad 
above , where it is comprejfed and indented at the top , re- 
fembling an inverted Jhield armed with the acute jlyle , 
which is reflexed. 
This genus of plants is ranged in the fourth feftion 
of Linnaeus’s fixth clafs, which includes thofe plants 
whofe flowers have fix flamina and four ftyles. 
The Species are, 
1. Petiveria {Alliacea) floribus hexandris. Hort. Cliff. 
141. Petiveria with fix flamina in the flowers. Verbe- 
na aut fcorodonke affinis anomala, flore albido calyce 
afpero, alii odore. Sloan. Hift. 1. p. 17 1. commonly 
called Guinea Henweed. 
2. Petiveria ( OTandra ) floribus oflandris. Lin. Sp. 
Plant. 486. Petiveria with eight flamina in the flowers. 
Petiveria folani foliis, loculis fpinofls. Plum. Nov. 
Gen. 50. 
The title of this genus was given to it by Father 
Plumier, who difcovered it in America, in honour of 
Mr. James Petiver, an apothecary of London, who 
was a curious botanift. 
The firft is a very common plant in Jamaica, Barba- 
does, and moft of the other iflands in the Weft-In- 
dies, where it grows in fhady woods, and all the fa- 
v^nnas, in fuch plenty, as to become a troublefome 
weed ; and as this plant will endure a great deal of 
drought, it remains green when other plants are 
burned up, which occafions the cattle to browze on 
it ; and having a moft unfavoury ftrong fcent, fome- 
what like wild Garlick, it gives the cows milk the 
fame flavour, and the cattle which are killed foon 
after feeding on this plant, have a moft intolerable 
fcent, and their flefh is good for little. The roots are 
ftrong, and ftrike deep in the ground; the ftalks 
rife from two to three feet high ; they are jointed and 
become ligneous at bottom, and are garniflied with 
oblong leaves three inches long, and an inch and a 
half broad, of a deep green, and veined ; thefe are 
placed alternately upon fhort foot-ftalks. The flow- 
ers ate produced in {lender fpikes at the end of the 
branches ; they are very fmall, fo make no figure. 
They appear in June, and are fucceeded by fhort feed- 
veffels fhaped like an inverted fhield, containing one 
oblong feed which ripens in the autumn. 
The fecond fort is very like the firft, from which it 
differs in having a fliorter and narrower ftalk, and 
the flowers having eight flamina ; but unlefs theft 
marks are diftinguiflied by a nice obferver, they may 
both pafs for one plant. 
In Europe, thefe plants are preferved in the gardens 
of thofe perfons who are curious in botany ; but they 
have little beauty, and having fo ftrong rank fcent 
upon being handled, renders them lefs valuable. 
They are propagated by feeds, which muft be fowii 
on a hot-bed early in the fpring, and when the plants 
are come up, they fhould be each tranfplanted into a 
feparate pot, and plunged into a moderate hot-bed to 
bring them forward. When the plants have obtain* 
ed a good fhare of ftrength, they fhould be inured 
to bear the open air by degrees, into which they may 
be removed toward the latter end of June, placing 
them in a warm fituation, where they may remain 
till autumn, when they fhould be removed into the 
ftove, and in winter muft have a moderate degree of 
warmth, otherwife they will not live in this country. 
They will produce flowers and feeds every fiimmer, 
and will continue feveral years, remaining conftantly 
green throughout the year, and may be propagated 
by flips or cuttings. 
P E T R E A. Houft. Gen. Nov. Lin. Gen. Plant. 682. 
The Characters are, 
The flower hath a bcll-jhaped empalement of one leaf , cut 
into five large obtufle flegments almofi to the bottom , which 
are coloured , expanded and permanent. The flower hath 
one petal , having a fhort tube , but is cut above into five 
almofi equal flegments , which are expanded. It hath four 
fhort flamina fituated in the tube , two of which are a lit- 
tle longer than the other , terminated by fingle fummits , and 
four germen fupporting a fender Jlyle , crowned by an obtufle 
fiigma. The germen afterward become flour feeds wrapped 
up in a fringed cover. 
This genus of plants is ranged in the fecond fedtion of 
Linnsus’s fourteenth clafs, which includes thofe 
plants whofe flowers have two long and two fhorter 
flamina, and the feeds are inclofed in a cover. 
IT he title of this genus was given to this plant by 
the late Dr. Houftoun, who difcovered it growing 
naturally at La Vera Cruz in New Spain, in honour 
of Lord Petre, who was a great encourager of bota- 
ny, and was poftefied of a noble colledlion of exotic 
plants. 
We have but one Species of this genus, viz. 
Petrea ( V olubilis ) frutefcens foliis lanceolatis rigidis, 
flore racemofo pendulo. Shrubby Petrea with ftiff 
flpear -fhaped leaves , and flowers growing in long hanging 
bunches. 
This plant was firft difcovered by the late Dr, Houf- 
toun, growing naturally at La Vera Cruz in New- 
Spain, in 1731 , fince which time it was fent me 
from the ifland Berbuda, where it alfo grows natu- 
rally. It rifes with a woody ftalk to the height of 
fifteen or fixteen feet, which is covered with a light 
gray bark,, fending out feveral long branches ; thefe 
have a whiter bark than the flem, and are garnifhed 
with leaves at each joint, which on the lower part of 
the branches are placed by threes round them, but 
higher up they Hand by pairs ; they are about five 
inches long, and two inches and a half broad in the 
middle, drawing to a point at each end ; they are 
ftiff, and their furface rough, of a light green, hav- 
ing a ftrong dark midrib, with feveral tranfverfe veins 
running from the midrib to the borders, which are 
entire. The flowers are produced at the end of the 
branches growing in loofe bunches, which are nine or 
ten inches long, each flower Handing upon a flendet 
foot-ftalk about an inch long ; the empalement of the 
flower is compofed of five narrow obtufe leaves about 
an inch long, which are of a fine blue colour, fo are 
much more confpicuous than the petals, which arc 
white. 
