128 



ASCLEPIADE.E. XXIII. HOYA. XXIV. PTEROSTELMA. XXV. PHYSOSTELMA. XXVI. TYLOPHORA. 



short, subulate, erect, inner angles. ^ ^ S. Native of the 

 East Indies, at Korma, Hamilton, and at Segaen, Wall. Ham. 

 herb. no. 770. Wall. ascl. no. 24, f. 146, and 156, without a 

 name. Lakun of the Hindoos. 

 Lakun Hoya. Shrub tw. 



f f Species described by Vahl, under the generic name of 

 Sperlingia, which name ought to take precedence of Hoya, being 

 the oldest, which me have still retained, on account of that 

 name being generally received. Both species are probably 

 identical with two of those described above. 



36 H. VERTICILLA'TA ; climbing, rooting ; stems terete, gla- 

 brous ; leaves 4 in a whorl, petiolate, oblong, acuminated, acute, 

 fleshy, glabrous, veinless ; umbels pedunculate, copious ; pedi- 

 cels compressed, filiform ; segments of corolla triangular, acute 

 at both ends, retusely sub-bicornute outside, on the outer margin : 

 with inflexed, conduplicate edges ; corona a simple star, covering 

 the genitals, having the lobes equal in length to the segments 

 of the corolla, complicate, lanceolate, with an elevated line in 

 the middle, and a corresponding furrow on the opposite side, 

 yellowish, shining ; follicles 6-8 inches long, glabrous. b-^- 

 S. Native of the East Indies. Sperlingia verticillata, Vahl, in 

 act. soc. hist. nat. hafn. 6. p. 113. 



fVhorled-\eave& Hoya. Shrub twining. 



37 H. OPPOSITA ; leaves opposite, fj . ^\ S. Native of the 

 East Indies. Sperlingia opposita, Vahl, 1. c. p. 11 4. Nummu- 

 laria lactea major, Rumph. amb. 5. p. 470. t. 175. f. 1. Very 

 like H. verticillata ; but differs, in the opposite leaves, the nar- 

 rower petioles, which are convex beneath, and concave above ; 

 while, in that species, they are flattened and depressed, almost an 

 inch long, succulent, and articulated at the base. 



Opposite-leaved Hoya. Shrub twining. 



Cult, The species of Hoya all bear handsome waxy blossoms, 

 disposed in simple umbels. They grow freely in a mixture of 

 loam, peat, and sand, and are otherwise easily managed. They 

 are readily propagated by cuitings, in a moist heat. 



XXIV. PTEROSTE'LMA (from irrtpov, pteron, a wing; 

 and ortXyua, stelma, a crown ; leaflets of corona membranous.) 

 Wight, contrib. ind. bot. p. 39. 



LIN. SYST. Pentdndria, Digynia. Corolla rotate, 5-cleft. 

 Stamineous corona 5-leaved ; leaflets membranous, with re- 

 flexed sides : having the inner angles drawn out into subulate, 

 erect teeth. Anthers terminated by a membrane ; pollen masses 

 erect, fixed by the base to the back of the corpuscles. Stigma 

 apiculated. A twining ? or decumbent shrub. Leaves oppo- 

 site, oblong, acuminated, fleshy. Flowers rather large. Co- 

 rolla deeply 5-cleft ; with linear-lanceolate segments, and a 

 pilose tube. Margins of the leaflets of the corona conniving, 

 as the wings of butterflies are when sitting. This genus is 

 nearly allied to Hoya, both in habit, and in the structure of the 

 flowers, differing principally, in having foliaceous instead of 

 fleshy leaflets of corona, and in the dorsal not lateral attachment 

 of the pollen masses. 



1 P. ACUMINA'TA (Wight, 1. c.) Vj . ^. S. Native of Silhet. 

 Wall. ascl. no. 129, without a name. 



Acuminated-\ea.ved Pterostelma. Shrub ? 



Cult. See Hoya, above, for culture and propagation. 



XXV. PHYSOSTE'LMA (from 0v<m, physa, a bladder ; and 

 oreXyua, stelma, a crown ; leaflets of corona inflated.) Wight, 

 contrib. ind. bot. p. 39. 



LIN. SYST. Pentdndria, Dygynia. Corolla rotate, spreading, 

 repandly, 5-toothed. Stamineous corona 5-leaved ; leaflets in- 

 flated, opposite the anthers. Anthers terminated by a mem- 

 brane. Filaments bipartite from the base to the apex, each 

 alternate part bearing an anther, close together, alternating with 



the leaflets of the corona. Pollen masses fixed by the base, 

 erect, nearly cylindrical. Stigma depressed. A twining shrub. 

 Leaves opposite, ovate-lanceolate, acuminated, glabrous, fleshy. 

 Umbels lateral, on longish peduncles, few. flowered. Flowers 

 large. This curious genus is allied to Hoya in habit ; but is at 

 once distinguished from it, and every other, by the remarkable 

 division of the filaments ; there being 10 filaments and 5 anthers. 



1 P. WALUCHII (Wight, contrib. ind. bot. p. 40.) Pj . ^. S. 

 Native of Singapore. Wall. ascl. no. 130, without a name. 



Wallich's Physostelma. Shrub tw. 



Cult. For culture and propagation see Hoya, above. 



XXVI. TYLO'PHORA (Xoe, tylos, a swelling, and 

 <t>opitt>, phoreo, bear; in reference to the ventricose pollen masses). 

 R. Br. in mem. wern. soc. 1. p. 28. prod. p. 460. Hoya species, 

 Spreng. syst. 1. p. 843. 



LIN. SYST. Pentdndria, Digynia. Corolla rotate, 5-parted. 

 Stamineous corona 5-leaved ; leaflets simple, fleshy : having the 

 inner angles simple and toothless. Anthers terminated by a 

 membrane ; pollen masses erect, fixed by the base, with simple 

 margins, transverse or ascending, minute, ventricose. Stigma 

 mutic. Follicles smooth, attenuated at the apex, compressed, 

 rather angular on one side. Seeds comose. Twining herbs or 

 subshrubs. Leaves opposite, membranous, flat. Umbels inter- 

 petiolar, or disposed alternately along a common peduncle. 

 Flowers usually small. 



The extreme minuteness of the pollen masses renders it diffi- 

 cult to determine the situation this genus ought to occupy in 

 the order. The form of the gynostegium and the leaves of the 

 corona readily distinguish it from every other genus except 

 Iphisia, but which differs in the pendulous pollen masses. As 

 now defined, this genus is quite distinct from Hoya, to which 

 Mr. R. Brown considered it so closely allied. Arnott. and 

 Wight, contrib. ind. bot. p. 50. 



1. Leaflets of Stamineous corona depressed, fleshy, toothless 

 inside, shorter than the gynostegium. Species natives of Neni 

 Holt and. 



1 T. GRANDIFLORA (R. Br. prod. p. 460.) umbels nearly ses- 

 sile, simple, few-flowered ; pedicels glabrous ; leaves cordate- 

 ovate, acute, and are, as well as the branches, downy. T? . *"*. S. 

 Native of New South Wales, about Port Jackson. Hoya gran- 

 diflora, Spreng. syst. 1. p. 843. 



Great-flowered Tylophora. Fl. Ju. Jul. Clt. 1822. Sh. tw. 



2 T. BARBA'TA (R. Br. 1. c.) umbels usually twin ; common 

 peduncles shorter than the leaves ; corolla bearded ; leaves ovate, 

 acute, quite glabrous. J; . *"\ S. Native of New South Wales, 

 about Port Jackson. Hoya barbata, Spreng. syst. 1. p. 843. 



Bearded Tylophora. Fl. June, Jul. Clt. 1822. Shrub tw. 



3 T. FLEXUOSA (R. Br. 1. c.) umbels alternate, sessile; com- 

 mon peduncles flexuous ; leaves cordate-oblong, veiny ; corolla 

 beardless. Pj . ^\ F. Native of New Holland, within the 

 tropic. Hoya flexuosa, Spreng. syst. 1. p. 813. 



Flexuous Tylophora. Shrub tw. 



4 T. VELUTINA ; stem twining ; leaves cordate-ovate, acu- 

 minated, tomentose ; flowers cymose ; throat of corolla naked. 

 \l . *"\ S. Native of New Holland. Pergularia velutina, 

 Spreng. syst. 1. p. 844. 



Velvety Tylophora. Shrub tw. 



5 T. PANICULA V TA (R. Br. 1. c.) panicles dichotomous ; seg- 

 ments of corolla ligulate above : leaves ovate, acuminated, 

 smoothish : lower ones subcordate. f? . r ^. S. Native of New 

 South Wales, about Port Jackson. Hoya paniculata, Spreng. 

 syst. 843. 



Panic/ed-fiowereA Tylophora. Shrub tw. 



2. Leaflets of Stamineous corona very blunt, or bluntly 



