A Potential Weed. 151 



A POTENTIAL WEED. 



A RA L 'JIA SERICIFERA . I^rot . 



By E. P. Phillips, M.A., D.vSc, F.L.S., Division of Botany 



Pretoria. 



In 1903 Mr. J. Burtt-Davy, then the Government Botanist, drew 

 attention to a creeper which was reported as hecomin^' a great nuisance 

 in some Johannesburg gardens. Since then apparently notliing has 

 been written on the spread of this plant in South Africa. 



The genus Araujia occurs in Brazil where it is represented by 

 about ten species of which A. sericifera, Brot., appears to be the 

 best known, having been introduced into many countries as an orna- 

 mental plant. This species is known to seedsmen under the names of 

 Araujia aJhens and Physianthus albens, and popularly known as the 

 Moth Catcher or Cruel Plant. 



Kerner (Natal History of Plants) menticms that " in its <iwn 

 countrj:^ it {Araujia sericifera) is visited by humble bees .... in 

 other localities its sweet smelling tubular flowers are visited by hosts 

 of moths Avhich are apparently unacquainted with the mechanism of 

 the pollen masses, etc., and get trapped by their probosces in the slit- 

 like notches which are present between the anther wings." 



The plant, which is a climber, belongs to the natural order 

 Asclepiadaceae (represented in South Africa by several melkbossies, 

 carrion flowers, etc.). All parts of the plant exude a milky juice 

 when cut. The leaves are opposite, stalked, 2-3 inches long, and 

 about 1-1^ inches broad at the l>ase ; they are more or less oblong in 

 outline, square at the base, and ending in a pointed apex, quite devoid 

 of hairs, dark green above, and a paler green beneath. The flowers 

 which are borne in the axils of the leaves are a creamy white and 

 sweet smelling. The seed pod is a large green egg-shaped fleshy body 

 up to 6 inches long, and over 2 inches in diameter at the base, with a 

 deep grove on one side. The seeds, which are about ^/^ inch long, end 

 in a long tuft of silky hairs. When the fruit is ripe it splits down one 

 side, and the seeds may be carried by the wind long distances from 

 the parent plant. 



There is no record as to when this plant was first introduced into 

 South Africa, but from reports received from time to time by the 

 Division of Botany, it has undoubtedly spread over most of the Union, 

 and has also been recorded from Swaziland. 



The plant is a very prolific seeder, and as the seeds are so well 

 adapted for wind distribution, it is no wonder that it is spreading so 

 rapidly. As the plant is a climber there appears to be little danger 

 of it invading the natural veld, but there is every possibility of it 

 becoming a nuisance in plantations, and it certainly is a nuisance in 

 gardens. The writer has seen poplar trees in Pretoria covered with 

 Araujia sericifera, and if it is allowed to grow un(diecked will probably 

 smother them. 



This article is merely to sound a note of warning as to the poten- 

 tial danger of the plant as a weed. It certainly should not be delilier- 

 ately cultivated as an ornamental plant, and Avhere plants are grow- 

 ing' it will be advisable to destroy them. 



