176 



AN ACCOUNT OF THE GENUS AKGEMONE. 

 By D. Prain. 



(Continued from p, 135.) 



The greatest difficulty in the treatment of the genus has been 

 experienced in the limitation of its species. Thus in 1799 Lesti- 

 boudois distinguished as A. aiha the white-flowered plant which 

 Lamarck had separated in 1784 as a variety of A. viejuc/ina : in 

 1812 Stokes distinguished as A. scvvalvis those specimens of A. 

 ?«£'A-/crt»a with six placentas. This last "species" is certainly not 

 a defensible one, for the number of valves in the capsule varies from 

 four to six on the same plant. The name, however, was legitimately 

 applied, and is not a mere synonym, like Moench's A. spinosa 

 (1784); Salisbury's A. versicolor (1789); and Spach's A. vnh/aris 

 (1839) — three names indicating as many deliberate attempts to 

 supplant the name used by Linnaeus and Tonrnefort. Lestiboudois's 

 A. alba was described and renamed A. alhijlora in 1815 by Horne- 

 mann, and figured under Hornemann's name by Sims in 1822. In 

 1817 Eafinesque described as A. alba a plant that is not the same 

 as Lestiboudois's A. alba; in 1821, however, and again in 1824, 

 DeCandolle reverted to the Lamarckian view, and included not only 

 Hornemann's A. albiflora (Lestiboudois's A. alba), but Eafinesque's 

 one as well, in his A. mexicana. In 1823 James distinguished still 

 another A. alba, somewhat different both from that of Lestiboudois 

 and that of Eafinesque. But alike in America and in Europe the 

 recognition of a white-flowered species apart from A. mexicana was 

 during the first quarter of the present century very half-hearted, 

 and most botanists in both hemispheres have been content to 

 recognise in it only a variety {alhijlora) of the best known yellow- 

 flowered species. It must not, however, be overlooked that the 

 cleavage is hardly the same in the two continents; the A. mexicana 

 var. albifiora of DeCandolle (1821) is practically Lamarck's plant, 

 and, even if it be held to include Eafinesque's one, is equivalent to 

 A. alba and A. platijceras; the A. mexicana var. albifiora of Torrey 

 (1828), which is, in the main, tliat of subsequent American authors, 

 is the quite difi'erent A. intermedia. 



In 1827 Link and Otto described as A. pldti/ceras the plant 

 which, though they did not know it, is the A. alba of Eafinesque, 

 and in the same year Sweet described the perhaps distinct A. 

 grandiflora; in 1828 Sweet separated from A. mexicana the yellow- 

 flowered plant characteristic of Mexico, as opposed to that of the 

 West Indies ; this Mexican plant he named A. ochroleuca. In 1830 

 Sweet named, without describing it, A. intermedia, which, though 

 Sweet did not know it, is the A. alba of James; in the same year 

 Penny described as A. Barclayana a plant that is only a form of 

 A. ochroleuca. In 1831 Hooker described as A. rosea a plant from 

 Chili that is perhaps only a variety of A. plati/ceras ; what is 

 certainly only another form of A. rosea was described in 1833 as 

 A. Hnnnemannii by Otto and Dietrich. In 1834 Croom redescribed 



