374 
Prain . — The Mercurialineae and 
genus that Royen had based upon it, Linnaeus placed it in Croton as 
C. Ricinocarpos , Linn. (Sp. PI., ed. 2, 1427). Had the repudiation of Royen 
ended here our inquiry into the African Mercurialineae would not have 
been affected. But Linnaeus, in trying to place the Surinam portion of 
Ricinocarpos , Boerh., on a surer footing, obscured the identity of the African 
part. He balanced his omission of the American species in 1753 by the 
elision in 1763 of his own Mercurialis procumbens. This was to carry 
reparation too far ; though, even so, small harm need have happened had 
not Linnaeus endeavoured to account for the references under the African 
species. Two citations, Hermann’s of 1698 and Boerhaave’s of 1720, were 
transferred to Solandra capensis , Linn. (Sp. PL, ed. 2, 3407), the other two, 
his own of 1 737 and Royen’s of 1740, were repeated under Croton Ricino- 
carpos. Since the names of Hermann, Boerhaave, and Royen connote the 
same species it was inevitable that Linnaeus should find his action as regards 
the synonyms of Hermann and Boerhaave unsatisfactory. His personal 
copy of the second edition of the ‘ Species Plantarum ’ shows that, prior to 
1771, he struck his pen through both; the plant he had described as 
Solandra capensis proved to be a Hydrocotyle , which was republished in 1781 
by the younger Linnaeus (Suppl. PL, 176) as H m Solandra. Another home 
was sought for the unlucky synonyms ; they were cited in 1771 (Mantiss. 
PL, 298) under a new species collected in South Africa by Koenig and 
described as Mercurialis afra> Linn. Again the citation proved un- 
satisfactory; again the plant turned out to be a Hydrocotyle. In his own 
herbarium, Linnaeus struck his pen through the name Mercurialis afra , 
and wrote the sheet up afresh as Hydrocotyle villosa . The specimen is now 
in the Hydrocotyle cover, where it was laid by Linnaeus ; the name, published 
in 1781 by his son (Suppl. PL, 175), was unaccompanied by the synonyms 
of Hermann and Boerhaave, which Linnaeus thus left homeless after all. 
The plants of Solander and Koenig, identified in succession with Her- 
mann’s African Mercurialis , Boerhaave’s African Ricinocarpos , at any rate 
came from the Cape ; in each case, when he realized that these plants belonged 
to another genus, Linnaeus abandoned the synonyms. But the reduction 
of his own Mercurialis androgyna to his own Croton Ricinocarpos involved 
the assumption that M. androgyna differed generically from the African 
plant of Hermann and Boerhaave, and that it was a native of Surinam. 
The name M. androgyna , as used by Royen in 1740, connoted that African 
plant and no other ; this new citation by Linnaeus involved therefore 
a further repudiation of Royen. As, however, Royen was cited by Linnaeus 
along with himself, this repudiation, though undeniable, is manifestly 
unintentional. It is, therefore, more than probable that, even when he 
wrote Croton Ricinocarpos where he ought to have written Acalypha Ricino- 
carpos , Linnaeus did not really desire to discredit Royen. 
In the absence of any specimen written up by Linnaeus as ‘ Mercurialis 
