B O T 
' in thefe are generally difreganled, they will not, to an at¬ 
tentive obferver, appear lefs curioufly conftru&ed, than 
tliofe which boaft of gayer colours and more confpicuous 
parts. The folicitude of Providence for the prefervation 
of grades, is evident from this ; that the more the leaves 
are confhmed, the more the roots increafe. The great 
Author of Nature defigned, that the delightful verdure of 
thefe plants fhould cover the furface of the earth, and 
that they fhould afford nouriffiment to an alnioft infinite 
number of his creatures. But what increafes our admira¬ 
tion moli, is, that although the grades conrtitute the prin¬ 
cipal food of herbivorous animals, yet, wliilft they are left 
at liberty in the pafture, they leave untouched the draws 
which fupport the flowers, that the feeds may ripen and 
fow themfelves. Add to this, that many of the feemingly 
dry and dead leaves of grades revive, and renew their ver¬ 
dure in the fp.ring. And on lofty mountains, where the 
fummer heats are hardly Arfficient to ripen the feeds, the 
moft common grades are thofe which are viviporous, and 
confequently propagate themfelves without feeds. No part 
of botany, perhaps, at fir ft fight, appears more difficult 
than the ftudy of grades ; blit the method of accurate dif- 
fedtion and obfervation once adopted, no part is more cer¬ 
tain or more eafy. To gain a clear idea of the ffruflure 
of the flowers, they muff be examined juft before the an- 
therae difcharge their pollen; and by comparing them in 
that (fate with the example given in the plate, and with 
the generic defcription, the principal difficulties v\ ill foon 
"be furmounted. The botanic microfcope will be found 
extremely ufeful in diftedting the minuter parts of grades. 
The plants in this clafs are arranged under three orders, viz. 
Order i. Monogynia, comprehending fuch plants as 
have but one piftillum. This order contains thirty-four 
genera, diftinguifhed into, i. Thofewhofe flowers have no 
l’patha or amentum ; of which there ate fixteen, viz. Va¬ 
leriana, valerian; Olax ; Willichia; Tnmarindus, tama¬ 
rind-tree; Rumpfia; Cneorum, widow-wail; Camocladia, 
maiden plum ; Melothria, fmall creeping cucumber ; Or- 
tegia ; Loeflingia; Polycnemum ; Hippocratea ; Rotala ; 
Witfenia ; Pomereulia ; and Dilatris. 2. Such as have fpa- 
thaceous flowers, and a trilocular capfule ; of which there 
are ten, viz. Crocus, faffron; Ixia; Gladiolus, corn-flag; 
Antholyza; Iris, flower-de-luce ; Moraea ; Wachendorfia; 
Commelina, day-flower; Callifia ; and Xyris. 3. Such 
as have an imbricated amentum, and are gymnofpermous; 
of which there are eight, viz. Schcen.us, baftard cyprefs; 
Cyperus, greater galangale; Scirpus, rulh-grafs; Erio- 
phorum, cotton grafs ; Lygeum, hooded matweed;- Nar- 
dtts, mat-grafs; Kyllinga; and Fuiiena. 
Order 2. Dig ynia, comprehending fuch plants as have 
two piftilla. This order contains thirty-one genera, viz. 
Bobartiji; Cornucopia, horn-of-plenty grafs ; Saccharum, 
fugar-cane; Panicum, panic gyafs; Phleum, cat’s-tail grafs; 
Alopecurus, fox-tail grafs; Milium, millet; Agroftis, bent 
grafs; Aira, hair-grafs; Melica, melic, or rope-grafs ; 
Poa, meadow - gra fs ; Briza, quaking-grafs ; Uniola, fea- 
fide oats of Carolina ; Daifylis, cock’s-foot grafs ; Cyno- 
furus, dog’s-tail grafs ; Feftuca, fefctte grafs; Bromus, 
brome-grafs ; Stipa, feather-grafts; Avena, oats; Lagu- 
rus, hare’s-tail graft ; Arundo. reed ; Ariftida, oat-grafs; 
Lolium, darnel, or rye-grafs j Elymus, lyme-grafs; Se- 
cale, rye; Hordeum, barley; Triticum, wheat; Phalaris, 
canary-grafs ; Pafpalum; Rotthoella, fea-hard grafs; and 
Anthiftiria. 
Order 3. Trigynia, comprehending fuch plants as 
have three piftilla.. This order contains eleven genera, 
viz. Eriocaulon, net.wort ; Montia, fmall water chick- 
weed; Proferpinaca; Tripiaris 5 Holofteum; Polycar- 
pon; Mollugo, African chickweed; Minuartia; Queria; 
Lechea; and Koenigia. 
Example for Investigation. 
As a plant familiar to moft people, and growing in every 
part of the kingdom, we have chofen out of the fecond 
order of this clafs, the Avena, or oat, as a proper fiibjeCt 
■ Voii. HI, No. 129. 
A N Y. 2 6' 5 
to exemplify the fructification of grades. The parts are 
as follow ; Calyx, a a, fig. 11, magnified ; a glume gene¬ 
rally multiflorus, or many-flowered, bivSlvular, wrapping 
up the flowers loofely together, valves lanceolate, acute, 
ventricofe, loofe, large, awnlefs. Corolla, ^ -bival- 
vular, the inferior valve'hafder than the calyx, of the fame 
fize, .roundiffi, ventricofe, acuminate at both ends, emitting 
from the back an arifta or awn fpirally twilled, and bend¬ 
ing like a knee. Nectarium, c c, two-leaved; leaflets 
lanceolate, gibbom at the bafe. Stamina, s, fig. 12; fila¬ 
ments three, capillary ; antheras oblong, bifurcate. Pis- 
tillum, /; the germen, g, obtufe; ftyles two, reflex, pi¬ 
lous, in the upper part plumous; ftigmas fimple. Peri- 
carpium, fig. 13; none but the corolla, which fupplies 
its place, adhering clofe to the feed, which it involves 
without gaping. Seed, d\ (ingle, flender-oblong, acumi¬ 
nate at botli ends, marked with a longitudinal furrow__ 
See the article Avena, vol.ii. p.552. 
CLASS IV. TETRANDRIA. 
This clafs confifts of fuch plants as bear hermaphrodite 
flowers, furnilhed with four (lamina. The flowers of this 
clafs may be known from thofe of the fourteenth by this 
diftindlion, that the (lamina in thefe are of an equal length ; 
whereas in thofe of the fourteenth, which have four (la¬ 
mina likewife, there are two long and two (hort. The 
orders of this clafs are three, viz. 
Order 1. Monogynia, comprehending fuch plants as 
have but one piftillum. This order contains feventy ge¬ 
nera, diftinguifhed into, 1. Such as have aggregate flowers 
properly (0 called, with the feeds (ingle and naked ;‘of 
which there are (even, viz. Protea, filver-tree; Ce.phalan- 
tlnts, button-wood; Globularia, blue daify; Dipfacus, 
teazel; Knautia ; Scabiofa, fcabious; and Allionia.. 2. 
Such as have their flowers monopetalous on a double fruit, 
and the ftyle bifid, of which there are twenty, viz. Hedyo- 
tis; S.permacoce, button-weed; Sherardia, littie field mad¬ 
der ; Afperula, wood-roof; Diodia ; Knoxia ; Manettia ; 
Houftonia; Galium, lady’s bedflratv ; Crucianella, petty 
madder; Ru'oia, madder; Scabrita ; Fimbothrium ; Hy- 
drophylax ; Hartogia ; Acaena ; Banckfia ; Orixa ; Othe- 
ra ; and Skimmia. 3. Such as have monopetalous (lowers 
otherways circumftanced ; of which there are twenty, viz. 
Siphonanthus ; Catefbaea, lily-thorn ; Ixora, American 
jeflamine; Pavetta; Petefia; Mitchella; Callicarpa, John- 
fonia; Aquartia; Polyprennun, Carolina flax; Penaea ; 
Blaeria ; Buddleja ; Exacutn ; Plantago, plantain; Sco- 
paria ; Rhacoma ; Centunculus, bafe pimpernel ; Sangui- 
forba, greater wild bttrnet; Cift'us; and TEgiphila,. 4. 
Such as are tetrapetalous and complete, not wanting calyx 
or corolla ; of which there are twelve, viz. Epimedium, 
barren-wort; Cornus, dog-w'ood or cornelian cherry; Fa- 
gara ; Tomex ; Amannia ; Ptelea, flirub trefoil; Ludwi- 
gia, bafe Virginian loofefirife ; Oldenlandia ; Ifnardia ; 
Santalum, faunders ; Trapa, floating water caltrops; and 
Samara. 5. Such as are incomplete, calyx or corolla want¬ 
ing ; of which there are eleven, viz. Dorftenia, contra- 
yerva ; Elaeagnus, wild olive ; Krameria; Rivinia ; Salva- 
dora; Camphorofma; Alchetnilla, lady’s mantle ; Stru- 
thiola ; Cometes ; and Siriutn. 
Order 2. Dig ynia, compreliending fuch plants as have 
two piftilla. This order contains nine genera, viz. Apha- 
nes, par(ley-piert; Cruzita ; Buft’onia, toad-grafs ; Hama- 
melis, witch-hazel; Cufcuta, dodder ; Hypecouin ; Galo- 
pinn; Gomozia.; and Gonocarpus. 
Order 3. Tetragynia, comprehending fuch plants as 
have four piftilla. This order contains (even genera., viz. 
Ilex, holly; Coldenia; Potamogeton, pond-weed ; Rup- 
pia, Tea or tailed grafs ; Sagtna, pearl-wort; Myginda; and 
Tilkea, fmall annual houleleek. 
Example for Investigation. 
We have feledled from the fecond order of this clafs the 
plant lidrhamelis, or witch-hazel ; which, from its cn riot Is 
.fabric, will afford a very pleating delineation of its parts. 
- 3 V . Calyx? 
