v i i i I N T R Ó D U G T Ì O N.
Fig. K. Genus 10. Spbceria.
A Fungus, having numerous fpherical or oblong'vefic-les, regularly
arranged under feme part of its'.furface-/; which veikles'difchargi a duft
or powder,. There are two divifiori* of this' Genus," firft, agaric-likeV
growing on the ground, of a .foft filamentous fubftance, having a proper
root, volva, ftem, and-pileus j fecond, paraiitic, fettle, or Tup ported on
a pillar, and are generally of an hard, horny, ,or woody fubftance throughout.
The little figures at K. reprefent the Spuria tuberculofa,'and the
Sphmrtaagariciformis, a new ipecies, four or five inches high, with a
bulbous volyated root, a ftem, and a pileus. This is a very curious plant
and a true non-defcript, as will be feen in?fts proper place.
,Fig: L. Genus n. - Mvcor fMould or- MoulSnefsJ. \
A Fungus, confifting of a roundlih veficle, fupported on a filament
and containing numerous feeds, affixed to an hair-like receptacle. The
figure at L. reprefents the Mucor mucedo,Kis it grew on the ftalk-of t l l j r ,
which had afmall part of the fruit adhering to if, in a putrid ftate.
Thefe few characters being eftabliihed in the memory, it will be eafy
on fight of a fpecimen/ to-determine, properly and certainly, to which of
the above families it belongs. But the firft Genus—the Agarics—being
very numerous, and a perplexing fimilarity obtaining between fome of the
ipecies, it therefore becomes neceffary to' examine with care, the-form
texture, number, and fituation of the parts of the plant under review'
before we can difcover a certain difcriminative, fpecific mark, peculiar to
that fpecies, and not to be found in any other;—and till fucha mark be
difcovered, we- cannot truly fay, that the ipecies is< p l p e r l y defined or"
alccrtained. I would not here be.underftood to..mean, that wc are to difcover
a part in every fpecies, which is not to .be found in fome other," this
7 a,fimple fenfe is impoffible; but the diftinguiihing mark.is to be'dif-
I -N;. T R O D "II. C T I O N. ix
covered by examining all the parts in a combined ór complicated fcene.
And when a plant is difcovered, concerning which we are doubtful whe- •
ther it is a fpecies of itfelf, or only a variety-of fpecies already known,
we ought carefully to collate it with the original, from which we fuppofe
it may poffibly be derived; «tod if we find it to agree in the.number, figure/
and fituation,df its'parts," and that the matter of which it is compofed,
agree in fubftance or texture, we may reafonably-fuppofe, that the
'doubtful plant is a variety and not a fpecies, though it may be much different,
in refpef -to time, foil, magnitude, colour, &c.
. On-the contrary, t h o u g h two plants may agree in colour, time, foil,
fituation, fize, M — 9 yet if they, difagree in any one effential
mark, we .are nevcrthelefs certain of their fpecific diftindion. For inftance
fuppofe the Agaricus fimitarius^ has an upright white ftem, growing
from a bulbous root," which is deftitute of volva; fo has the Agaricus
M M I Suppofe it further, to have a large white pileus, brown at the
apex, and covered here and there with Toft brown fcales ; fuppofe it to
have' a white curtain, and gills of a pale fleih colour, while young, and
c h a n g i n g their colour afterwards ; the Agaricus annulatus exhibits all the
above characters, is evidently as the.other. Thus far, therefore, no certain
fpecific mark is discoverable; but on examining them a little further
we find, that the gills of the fimetarius are arranged in one feries only,,
being all of equal length, and extended from the rim of-the pileus to the
top'of the ftem ; but in the annulatus they are arranged in feveral feries,
unequal: in length, which is a- certain mark of diftincftion in the two
fpecies. - This one diagnoftic being- found, we then fupport it by aids,
".drawn from habit, figure, foil, fize, duration, fmell, tafte, colour, and
diffolutiom; all which being properly attended to, will, with the afliftance
of application to the ftudy, and actual oBfervation made upon the .plants in
the different ftages of growth, render the knowledge of their fpecific diftin£
tions, both eafy and certain.
To explain a little, further what I mean, by. aids to fupport the fpedfic
mark, in the above inftance, The pileus in -the. Agaricus frnitarius, is -of I H I . . au