106 



ASCLEPIADE.E. 



ORDER CLIII. ASCLEPIA V DE.<E (this order contains plants 

 agreeing with Asclejnas in important characters). R. Br. in 

 wern. soc. mem. 1. p. 19. prod. 458. Apocynese, part. Juss. 

 gen. p. 143. Adans. fam. p. 160. Contortae, part. Lin. 



Calyx 5-cleft or 5-parted (f. 16. a. f. 17. a.), permanent. 

 Corolla monopetalous (f. 16. 6. f. 17. c. f. 20. 6.), hypogynous, 

 5-lobed (f. 16. b. f. 17. b. f. 20. &.), regular, imbricate in es- 

 tivation (f. 20. 6.), rarely valvate, deciduous. Stamens 5, in- 

 serted in the bottom of the corolla, alternating with the seg- 

 ments of the limb ; filaments usually connected ; anthers 

 2-celled (f. 17. h. f. 15. d.) t but sometimes almost 4-celled 

 from a semi-complete dissepiment in each of the true cells ; pollen 

 at the bursting of the anthers coalescing in an equal number 

 of masses to the cells of the anthers, rarely twin or confluent 

 by pairs, or by fours, or solitary, fixed to the 5 processes of 

 the stigma. Ovaria 2. Styles 2, close together, often very 

 short ; stigma common to both, dilated, pentagonal : having the 

 angles bearing corpuscles. Follicles 2, one of which is often 

 abortive : having the placenta applied to the suture, but is at 

 length free. Seeds numerous, imbricate, pendulous, usually 

 furnished with a tuft of hairs at the umbilicus. Albumen twin. 

 Embryo straight, with foliaceous cotyledons, a superior radicle, 

 and inconspicuous plumule. Shrubs, rarely herbs, for the most 

 part lactescent and climbing. Leaves entire, usually opposite, 

 but sometimes also alternate and verticillate, usually furnished 

 with intrapetiolar cilia in place of stipulas. Flowers subum- 

 bellate, fascicled or racemose, interpetiolar. 



This differs from all other dicotyledonous orders in the pollen 

 of all the anthers in each flower being combined in a definite 

 number of masses of a waxy substance, which, at the bursting 

 of the anthers, are fixed to the 5 glandular processes of the 

 stigma ; in this structure it has some analogy with Orchidece, a 

 monocotyledonous order. It differs from Apocynece, to which 

 it is nearly allied, in having the stamens united into a fleshy 

 crown, and in the substance of the anthers. 



Periploca glabra is the only instance of an Asclepiadeous 

 plant being a hardy shrub ; every other woody species of the 

 order being natives of hot countries. The genus Hbya com- 

 prehends fleshy-leaved, climbing, or creeping plants, with 

 umbels of waxen odoriferous flowers, distilling honey. Per- 

 gularia is valued for its fragrance ; Ceropegia and other genera 

 for their singularity ; and Asclepias for beauty and hardiness. 

 But the most remarkable genera of the order are Slapelia, 

 Duvalia, Pectinaria, O'rbea, Tnddntia, Huernia, Piar6nthus, &c. 

 in which the stems are fleshy and of various forms, and the 

 leaves supplied by small thick points or scales, and whose 

 flowers are not less singular for their curious organization, than 

 they are for their colouring and spotting, and offensive for their 

 odour. The root of Diplolepis vomitorium, Asclepias curas- 

 sdvica, Colotropis procera, and some others is employed in 

 different countries for ipecacuanha. An infusion of the root of 

 Asclepias decumbens has the singular property of exciting 

 perspiration, whence it is successfully used in Virginia for 

 pleurisy. 



Notwithstanding the poisonous nature of the greater number 



12 



of the species of this order, yet the young shoots of some are 

 used as an article of food ; of this nature are Perguldria edulis, 

 Oxystelma esculentum, Hemidesmus I'ndicus, and some others. 



Synopsis of the genera. 

 TRIBE I. 



ORTHOPHURA'MLE. Asclepiadeee veree, part. R.Br.inmem. 

 rvern. soc. I. p. 21. Pollen masses 10, erect (f. 15. d.} or conni- 

 vent, smooth, fixed by pairs to the corpuscles of the stigma : 

 that is 5 2-celled anthers, separable into 2 parts by a longi- 

 tudinal furrow. 



SDBTRIBE I. STAPELIE\E. Pollen masses erect (f. 16. d.) or 

 connivent, lying on the stigma, fixed by the base or beneath the 

 middle of the side. Anthers simple at top, that is, not terminated 

 by a membrane. 



\. Column of fructification or gynostegium inclosed. Stami- 

 neous corona appendiculate outside. 



1 CEROPE'GJA. Tube of corolla ventricose from the base ; 

 limb 5-parted, with ligular, conniving segments. Stamineous 

 corona double ; leaflets of the inner corona opposite the lobes 

 of the outer one. 



2 HUE'RNIA. Corolla campanulate, with a 10-cleft limb : 

 having the 5 accessary segments short. Corona double : outer 

 one 5-cleft, with bifid segments : inner one of 5 leaflets, altern- 

 ating with the segments of the outer one. 



3 PIARA'NTHUS. Corolla campanulate, 5-cleft; corona sim- 

 ple, 5-leaved ; leaflets dentately crested on the back. 



2. Column of fructification, or gynostegium, exsertedor semi- 

 exserted, appendiculate outside. Pollen masses having one of 

 the edges or margins pellucid. 



4 STAPE'LIA. Corona double : outer one of 5 undivided 

 leaflets, which are usually toothed on the back ; leaflets of the 

 inner one opposite the anthers, sometimes obsolete. 



5 GONOSTE V MON. Corona double : outer one of 5 distinct, 

 canaliculate, obtuse, mucronate leaflets : of the inner one unci- 

 form, obtuse, opposite the anthers, sometimes obsolete. 



6 PODA'NTHES. Corona double : outer one 5-parted to the 

 middle ; the segments channel-formed, rhomboid, deeply emar- 

 ginate or bifid : those of the inner form of a reversed foot. 



7 TRIDE'NTEA. Corona double : outer one of 5 tridenti- 

 form, distinct leaflets: those of the inner corona unequally bi- 

 partite. 



8 TROMOTRICHE. Corona double : outer one 5-parted to the 

 base ; with cuneate, rhomboid, or serrated, horizontal segments ; 

 leaflets of the inner unequally bipartite ; inner branch longer, 

 recurved, clavate. Corolla smooth, not wrinkled or corrugated 

 as in the other genera separated from Stapelia, ciliated with 

 clavate trembling glands. 



9 O'RBEA. Corona double : outer one of 5 long, spreading, 

 bi-tridentate leaflets ; of the inner unequally bifid, having the 

 inner branch longer, incurved, and clavate at apex. Corolla 



