34 THE VOYAGE OF ILM.S. CHALLENGER. 



Helena, having also been found in Ascension deserves examination and discussion in this 



place. 



Commidcndron rugosum, DC, one of the St Helena small arboreous Composite, is 

 recorded from Ascension by a no less competent and trustworthy authority than Burchell, 

 who spent five years in St Helena, and was perfectly familiar with every plant. This 

 record was first published, in an abbreviated form, in Hooker's Icones Plantarum, xi. p. 45, 

 and subsequently copied by Melliss in his St Helena. It was first copied from a uote, 

 in Burchell's handwriting, on the back of a drawing of Commidendron rugosum in the 

 collection of Burchell's drawings of plants, scenery, &c, of St Helena, in the Herbarium 

 library at Kew. The whole note runs thus : " This plant was found growing wild in the 

 Green Mountain at Ascension, but very scarce, and furnishes the principal food for the wild 

 goats. 26. 1. 17." This is written beneath the original inscription : " Scrubwood or 

 gum-shrub, from between Longwood and Gregory's. 18. 5. 1810." In Burchell's manu- 

 script there is evidence that he was at Fulham in 1817, and within a fortnight of the date 

 given, so that it must have been written from memory or copied from some other docu- 

 ment. AVhen he was at Ascension, if ever, we have not been able to ascertain ; the only 

 mention of the island in his voluminous manuscript notes at Kew that we have seen is the 

 one in question. But Burchell was so exceedingly exact in all his entries, and so thoroughly 

 reliable in everything that can be verified, that we cannot reject his testimony, simply 

 because it has not been corroborated. 



The second plant is Wahlenbergia linifolia, ADC., which De Candolle himself 1 records 

 from Ascension thus: "In Sancta Helena (L. Banks! Lindl. ! Kunth!) et in ins. Ascen- 

 sionis (Herb. Herat!)." 



The third is Nephrodium cognatum, Hook., recorded by Kuhn (Filices Africanaa, p. 

 128) from Ascension, in Hb. Miquel. Of course it should be kept in view that all three 

 of these records may be wrong ; still, the probabilities of a common origin of the vegeta- 

 tion of the two islands are sufficiently strong to justify the publication of the slenderest 

 evidence bearing thereon. The recent discovery in South Trinidad, by Dr Balph Copeland, 

 of Asji/ciiiutit cmupressum, a distinct species of fern previously only known from St Helena, 

 may be adduced as another possible link in the chain of evidence of these islands having 

 derived their vegetation from the same source. It has already been mentioned that the 

 Ascension and St Helena species of Iledyotis are as dissimilar as any two species of this 

 large genus, and it may be added of the Ascension endemic Euphorbia origanoides that its 

 nearest ally is Euphorbia, trinerviaiiom the Guinea coast, while the genus Euphorbia is not 

 represented in the flora of St Helena by any certaiuly indigenous species. On the other 

 hand, ot the fourteen vascular cryptogams found in Ascension, seven also occur in St 

 Helena, and one is more nearly related to endemic St Helena species than to any others. 



1 Prodromes Syst. Nat. Beg, Veg., vii. p. 438. 



