Raphanusraphanistrumandsativushaveoftenbeenrankedasdistinctspecies，andowingtodifferencesintheirfruitevenasdistinctgenera;
butProfessorHoffman（’Bot。Zeitung’1872page482）hasnowshownthatthesedifferences，remarkableastheyare，graduateaway，thefruitofR。
caudatusbeingintermediate。BycultivatingR。raphanistrumduringseveralgenerations（ibid1873page9），ProfessorHoffmanalsoobtainedplantsbearingfruitslikethoseofR。sativus。
PEA（Pisumsativum）。
Mostbotanistslookatthegarden—peaasspecificallydistinctfromthefield—pea（P。arvense）。ThelatterexistsinawildstateinSouthernEurope;buttheaboriginalparentofthegarden—peahasbeenfoundbyonecollectoralone，ashestates，intheCrimea。（9/81。Alph。DeCandolle’Geograph。Bot。’960。Mr。Bentham’Hort。Journal’volume91855page141