53 
Order XXXV. LOASACEJE. 
LoasejE, Juss. Ann. Mus. 5. 18. (1804) ; Diet. Sc. Nat. 27. 93. (1823) ; Kunth. in Nov. 
Gen. et Sp. 6. 115. (1823) ; DC. Prodr. 3. 339. (1828.) 
Essential Character. — Calyx superior or inferior, 5-parted, persistent, spreading 
in aestivation. Petals 5 or 10, arising from within the recesses of the calyx, cucullate, with 
an indexed valvate aestivation ; the interior often, when present, much smaller than the 
outer, and truncate at the apex. Stamens indefinite, in several rows, arising from within 
the petals, either distinct or adhering in bundles before each petal, within the cavity of 
which they lie in aestivation; filaments subulate, unequal, the outer ones frequently desti- 
tute of anthers. Ovary inferior, or nearly superior, 1 -celled, with several parietal placentae, 
or with 1 free central lobed one; style single; stigma 1, or several. Fruit capsular or 
succulent, inferior or superior, 1 -celled, with parietal placentae originating at the sutures. 
Seeds numerous, without aril ; embryo lying in the axis of fieshy albumen, with the radicle 
pointing to the hilum, and fiat small cotyledons. — Herbaceous plants, hispid, with pungent 
hairs secreting an acrid juice. Leaves opposite or alternate, without stipules, usually more 
or less divided. Peduncles dJLiWoxY, 1-fiowered. 
Anomalies. Ovary sometimes almost superior. Seeds definite in Mentzelia and 
Klaprothia. 
Affinities. Distinguished from Onagraceae by their unilocular ovaries 
and indefinite stamens, part of which are sterile ; and perhaps by the latter 
character, and the additional 5 petals, connected with Passifloracese, with which 
they also sometimes accord in habit. Their rigid stinging hairs, climbing 
habit, and lobed leaves, resemble those of some Urticaceae, with which, how- 
ever, they have nothing more of importance in common. On the same account 
they may be compared with Cucurbitaceae, with which they further agree in 
their inferior unilocular fruit, with parietal placentae, and in the very generally 
yellow colour of their flowers. This, indeed, is the order with which, upon 
the whole, Loasaceae must be considered to have the closest affinity. 
Geography. All American, and chiefly from the more temperate regions, 
or the tropics, of either hemisphere. 
Properties. Except the stinging property which resides in the hairs of 
some species, nothing is known of the qualities of these plants. 
GENERA. 
Klaprothia, H. B. K. Acrolasia, Presl. Caiophora, Presl. Gronovia, L. 
Mentzelia, L. Loasa, Adans. Blumenbachia, Schrad. Grammatocarpus, Prsl. 
Petalanthera, Nutt. Ortiga, Feuill. Bartonia, Sims. Scyphanthus, Sweet. 
Order XXXVI. CACTACE^. The Indian-Fig Tribe. 
Cacti, Jmss. Gen. 310. (1789) in part. — Cactoide^, Vent. Tabl. 3. 289. (1799). — Opun- 
TIACE.E, Juss. Diet. Sc. 144. (1825) in part . ; Kunth. Nov. G. et Sp. 6. 65. (1823). 
— Nopaleac, DC. Theorie Eltm. 216. (1819).— Cacte^, DC. Prodr. 3. 457. (1828) ; 
Revue des Caciees (1829). Mem. Mus. (1829). Link and Otto in Verhand. des ver. 
Gart. Preuss. vol. in. p. 412 (1827) . Martius in act. Acad. Nat. Cur. XVI. (1832). — 
Sp^talume^, Nuttall Act. Philadelph. 7. 23. 
Essential Character. — Sepals numerous, usually indefinite, and confounded with 
the petals, either crowning the ovary, or covering its whole surface. Petals numerous, 
usually indefinite, arising from the orifice of the calyx, sometimes irregular. Stamens 
indefinite, more or less cohering with the petals and sepals ; filaments long, filiform ; anthers 
ovate, versatile. Ovary fieshy, inferior, 1 -celled, with numerous ovules arranged upon 
parietal placentae, equal in number to the lobes of the stigma; style filiform ; stigmas nu- 
merous, collected in a cluster. Fruit succulent, 1 -celled, many-seeded, either smooth, or 
covered with scales, scars, or tubercles. parietal, or, having lost their adhesion, nest- 
ling in pulp, ovate or obovate, without albumen ; embryo either straight, curved, or spiral, 
with a short thick radicle ; cotyledons fiat, thick, foliaceous, sometimes almost obsolete) in 
