1 



Oxalis in Ceylon. 



BY 



T. FETCH, B.A., B.Sc. 



N many of our up-covmtry tea districts the weed par 

 excellence on tea estates is Oxalis, or Manickwatte weed, 

 usually, when a scientific name is required, knowoi as Oxalis 

 violacea. The name Manickwatte weed is derived from Manick- 

 watte estate, where, in 18C0, the tea fields formerly in coffee 

 were said to resemble clover fields if left for any length of 

 time unweedcd, owing to the growth of this plant. (Pera- 

 deniya MSS.) As in the case of many other common weeds, 

 its origin in Ceylon is by no means clear, and the evidence 

 on the point is largely negative. The following account 

 summarizes what is available. 



To begin with, it may be pointed out that, in addition to 

 the native yellow-flowered Oxalis corniculata, the Hin-emtul- 

 embiliya of the Sinhalese, there are two species of Oxalis 

 occurring as introduced weeds in Ceylon. This fact was known 

 to Trimen, but it has been most unaccountably overlooked by 

 later botanists. In Trimen 's " Hortus Zeylanicus," published 

 in 1888, he listed the two, one as Oxalis latijolia H.B.K., and 

 the other, with a query, as Oxalis violacea L. The queiy mark 

 was probably misplaced by the printer, for on the herbarium 

 specimens named by Trimen it is attached to the one assigned 

 to 0. latijolia. It has previously been recorded that the 

 latter, which is the common Manickwatte weed, is Oxalis 

 corymbosa DC. (Ann. Perad., V., 541), and this identification 

 has now been confirmed by Kew. The other, less common 

 species, which is the Oxalis violacea of Trimen's " Hortus 

 Zeylanicus," has been identified by Kew as Oxalis latijolia 

 H.B.K. As far as is knowni, 0. violacea is not found in Cejdon. 



Oxalis violacea was recorded as growing in Cej'lon by Moon 

 in his " Catalogue of the Indigenous and Exotic Plants growing 

 in Ceylon," published in 1824. *It was one of the plants which 

 had not been recorded by any one previously, and, as with 

 very many of the plants recorded for the first time by Moon, 



Annals of the Royal Botanic Gardens, Peradeniya, Vol. VII., Part I., July, 1919. 



