It is also most instructive to compare-but I have not space here to enter on details-the evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties, with the evidence from fertility adduced by different hybridisers, or by the same observer from experiments made during different years.
Halaber oso irakasgarria da-hemen xehetasunetan sartzeko lekurik ez dut baina-honako hauek konparatzea, alegia, gure botanikaririk onenek, zenbait dudazko forma espezietzat ala aldakitzat sailkatu behar diren erabakitzeko emaniko frogak, hibridatzaile ezberdinek edo behatzaile berak urte ezberdinetan eginiko esperimentuen arabera ugalkortasunetik atera dituzten frogekin.