876 
ting fuch alterations and additions to the 
Rev. BENJAMIN CRACKNELL, Ware- 
ham, Dorfetthire, ¢hey /hall be inferted in 
@ general Appendix, after. the county lifts 
for England are all printed. 
War cham, Boi, 
Dec. 16, +796. 
PROCEEDINGS OF THE NATIONAL 
INSTITUTE. 
An Analyfis of a Memoir on tbe Organiza- 
zion of Monccotyledonous Vegetables, read 
to the firft Clafs of the National Tnftitute, 
by Citizen DEsFONTAINES. 
ALL feeds, befide the germ, confift of 
«+ one or two lobes, which form, at the 
ee of vegetation, the femi- 
al leaf, or leaves, whofe office is to nou- 
vith the young plant, till its roots are 
fufficiently large to fupply it with food, 
obtained from the earth in which it ts 
placed: 
tables into fuch as have one feminal leaf, 
and are called monocotyledonous ; and 
fuch as have two feminal leaves, and are 
thence named dicotyledonous. Thefe 
two general diftinétions, eftablifhed by 
Cefalpinus, have been admitted by feve- 
ral eminent botanifts, fuch as Ray, Boer- 
haave, Heifter, Vanroyen, Juflieu, &c., 
and been employed to advantage in their 
feveral ar rangements. 
The difcoveries cf Bernard Juffien, 
Hedwig, and Soe Warrant us in ar- 
ranging the Fulices, Muici, and Aleve, 
among ‘the " ronocoty ledonous. a 
In tke following obfervations, on the 
ftructure of Monocoty ledonous Vege- 
tables, the examples will, for the moft 
part, be drawn from fuch plants as have 
a ligneeus fem, the fubitances of which 
they are compofed being more apparent 
than in fuch plants as have herbaceous 
ftems, with the additicnal advantage of 
being capable of being examined in any 
feafon of the year. 
Ee of dicotyledonous vege- 
tables confit of the following parts: 
the EPIDEKMIS, or ozter bark, which a 
good deal refembies a very thin piece of 
parchment; it is pierced with innume- 
rable minute pores, through which iffues 
the infenfible perfpiration ; and when 
deftroyed, is capable of being re-pro- 
duced: Under this, is found a fecond 
covering, called the CELLULAR MEM- 
BRANE, or wadale bark, a fucculent fub- 
fence, generally green, formed of {mall 
4 
{tems 
Proceedings of the National Infiitute, 7 
hence refults-a divtfion of vege-_ 
[Dec. 
rounded granulations, abounding with 
veficles, and mixed with very fine fila- 
ments extending in all direétions ; it ap- 
pears to differ from the pith, m {careely 
any thing except colour ; the iazer bark, 
placed between the cellular. membrane 
and the wood, is compofed of {mall plates, 
feparable from each other by maceration, 
and confifting of an affemblage of /ap- 
veffels and air- bes, befides the veffels ne- 
ceflary to their own nourifhment. This 
inner bark is annually renewed. The 
wood confifts of the old inner barks, dif- 
poled in concentrie cylinders, of which 
the inner part, called the heart, is of z 
firmer texture, and deeper colour, than 
the outer. The centre of the ftem or 
trunk is occupied by the pit, from 
which proceed a number of divergent 
rainifications and proceffes, reaching 
through the ligneous fibres, as far as 
the inner bark. 
The ftems of monocotyledonous vege- 
tables confift of moft of the above-men- 
tioned fubftances ; but with fuch marked 
differences of ftructure, as- to eftablith 
two grand natural divifions of plants. 
Thefe variations will be pointed out by 
obfervations made en the various claffes 
and genera of monocotyledonous plants, 
viz. the Palme, Gramina, Afparagi, 
Dracontia, the Bulbous- rooted, the Fi- 
lices, and Mafci. ; 
1. Patmos. A palm, at frft fight, dif- 
fers eflentially from an afh, a birch, or 
any tree with fo feminal. leaves ; the 
trunk i is a regular column, whefe fummit 
is crowned with a tuft of leaves difpofed 
circularly, one above the other : the new 
leaves, in fpring, pufh out from the top, 
while the older ones, placed below, wi- 
ther and, by degrees, detach themfelves 
from the tree, leaving thofe circular im- 
ee or rings, which denote the age 
f the tree, fo long as it continues to 
ee “The interior peculiarities of 
ftreéture are as remarkable-as the ex- 
ternal differences : if a /omguiudinal fec- 
tion be made, there will appear an af- 
femblage of lrgneous fibres, large, iclid, 
{fmooth, flexible, lightly compreffed, 
compofed of fimilar {maller fibres, the 
greater number parallel to the axis of 
the trunk, and reaching, without inter- 
ruption, from the top to the bottom ; 
theie are croffed and conneéted together 
by others placed obliquely, fo as to form 
a Ter} : acute angle with the former; and 
they may, with eafe, be feparated ‘from 
each other in young plants, or thofe old 
ones that are in a flate of decay: if a 
traufverfe fection be made, no concentric 
layers 
