230 PROCEEDINGS OF THE CAXADIAX INSTITUTE. 



PHYSIANTHUS ALBENS. 



By Charles Ahmstrong. 



Read before the Biological Section November Jf.th, 1889. 



The plant which I bring before your notice to-night belongs to the 

 Order Asclepiadece, a large order of more than 600 species, nearly 

 all of them vex-y beautiful climbing plants, some of the rest very 

 curious. 



Periploca Grceca is I think the only hardy shiiib iu the oi'der. All 

 the rest are natives of hot climates. The genus Hoya (the wax-plant 

 of our greenhouses) are fleshy-leaved creeping or climbing plants with 

 umbels of sweet wax-like flowers. The Pergidarias, climbing yellow 

 flowered plants, are also beautifully sweet. Sap of Gymnema Lacti- 

 ferum, a native of Ceylon, is used instead of milk where niilk is 

 scarce. Some others are used for food. On the other hand this 

 plant on the table, a Stapelia (you would think it a cactus) with 

 Duvalia, Orbea, Obesia, Tridentia and others in which the stems are 

 fleshy, with small points or bracts instead of leaves, have flowers rich 

 in colours and markings, but so oSensive in odor that they almost 

 make you sick; I might say that they smell like rotten meat. A few 

 of the order ai-e natives of our own country. You know them by the 

 names of ^. Cornuti (milk- weed), A. Tuherosa, (pleuri.sy root), etc. 



I have thus far trespassed on your time in order to give you some 

 idea of the strange difference which may exist in an ordei*. The 

 plant before us Ls the Physianthus Albens. The calyx is large, tive- 

 parted; corolla, companulately urceolate with five swellings outside at 

 the base, and a corresponding numljer of cavities inside; limb, 

 spreading a little, five-cleft ; column, inclosed ; stamineous corona of 

 five leaves ; leaflets, cucullate, furnished each with a horizontal scale 

 outside; anthers, terminated by a membrane; pollen, mas.ses pendul- 

 ous, fixed by their tapering tops ; stigma, ovate, two-horned at the 

 apex; follicles, ovate, ventricose, bent downwards, semi-bilocular ;^ 



