CLASS XVITI. ORDER XII. 
63 
Liste'ra. Corolla irregular ; lip 2-lobed, sessile, with no calli ; column apte- 
rous ; anther fixed by the base, (tway-blade.) 
Crani'chis. Corolla 5-petalled, resupinate, sub-ringent lip, vaulted behind 
C. Anther inserted, terminal, not caducous; masses of pollen farinaceous or 
angular. 
Poco'nia. Petals 5, distinct, without glands ; lip sessile, cowled, crested inter- 
nally ; pollen farinaceous, (snake-mouth.) 
Cymbid'^ium. Petals 5, distinct; lip behind, or inverted, unguiculate ; the 
lamina bearded ; style free ; pollen angular, (grass pink.) 
Arethu'sa. Petals 5. connate at the base; lip below growing to the style, 
cowled above, crested within ; pollen angular, (arethusa.) 
. Tripho'ra. Petals 5, distant, equal and connivent, without glands ; lip ungui- 
culate, f icullate; column spatulate, flattened, apterous, (three-bird-orchis.) 
Tipula'ria. Segments of the perianth spreading; lip entire, sessile, with a 
conspicuous spur at the base beneath ; column or style without wings, length- 
ened, free; anthers resembling a lid, permanent ; pollinia (or masses of pollen) 
4, parallel, (limodore.) 
Lipa'ris. Corolla spreading; petals 5; lip flat, expanded, entire, turned vari- 
ous v/ays ; column or style winged; pollinia 4, parallel, affixed to the summit 
of the stigma. 
Micros'/tylis. Lip flat, sagittate or deeply cordate ; column very small, 
round ; pollinia 4, loose. 
CoRALLORm'zA. Lip produced behind, adnate with the spur, or free ; pollinia 
4, oblique, not parallel, (coral-root.) 
Apleg"trum. Lip unguiculate, not produced at the base ; anther below the 
summit of the column ; pollinia 4, oblique, lens-like, 
Calyp'''so. Segments of the perianth ascending ; petals 1-sided ; lip ventri- 
cose, spurred beneath near the end; column petaloid, dilated; pollinia 4, 
Epiden'^drum. Pollinia 4, parallel, each mass with an elastic filament at the 
base ; style united with the claw of the lip into a tube, (vanilla plant.) 
ORDER II. DIANDRIA. 
.Cypripe'dium. Calyx coloured. 4-leaved, spreading; corolla 0; (by some the 
caiyx''is called a corolla ;) nectary large, hollow, inflated ; style with a terminal 
lobe, and petal-like appendage on the upper side, (ladies' slipper.)* 
ORDER v. PENTANDRIA. 
Plants hear'mg seeds in follicles, and pollen in masses called pollinia. 
Ascle'pias. Petals 5, reflexed ; nectaries 5, concave, erect, containing little 
norns ; each stamen with a pair of pendulous masses of pollen suspended from 
the top of the stigma ; follicle smooth, (milk-weed, silk-weed. )t 
Apoc'ynum. Corolla bell-form ; stamens with converging anthers, proceed- 
ing from the middle of the stigma, and alternating with 5 nectaries; siigma 
thick, almost sessile; follicles in pairs, long linear, (dog-bane, Indian hemp.) 
Acera'tes Corolla reflexed ; 5 concave, short nectaries; each stamen with 
a pair of pendulous masses of pollen ; follicle smooth ; corolla with purple tips, 
much longer than the calyx. 
Gonolo'bus. Corolla wheel-form, 5-parted; nectary cylindric, fleshy, 5-lobed ; 
anthers opening transversely, terminated by a membrane; pollinia 5 pairs, not 
separating into grains; stigma flat; follicle 2, ventricose ^ seeds comose. 
(false choke-dog.) 
Periplo'ca, Calyx 5-cleft ; corolla rotate, 5-parted ; orifice surrounded with 
an urceolate crown, terminating in 6 filiform awns ; style 1 ; stigma 5-cornered ; 
pollinia solitary, composed of 4 grains ; follicles 2, divaricate, (milk- vine.) 
ORDER VI. HEXANDRIA. 
ARisTOLo'cmA. Calyx 0; corolla superior, 1-petalled, ligulate, inflated at the 
base ; capsule 6-celled, many-seeded, (birthwort.) 
ORDER XII. POLYANDRIA. 
As^ARUM, Calyx sub-campanulate, 3 to 4-cleft ; corolla 0 ; anthers adnate to 
the middle of the filaments; capsule inferior, 5-celled, crowned with the calyx, 
(wild ginger.) 
* The ladies' slipper of the garden belongs to the geTiusImpafiens, of the class Pentandria. 
t The genera in Ihi;^ orJer arc, by many botanists, placed in the class Pentandria. 
