Määritelmä: There is no evidence that the organism produces compounds (allelochemicals) that influence the growth, survival, and reproduction of other organisms.
Määritelmä: The percentage of organic carbon divided by the percentage of total nitrogen in organic material is lower than 23.
Kommentti: USDA Plants database specifies the organic material as either the above ground biomass of an herbaceous plant or the above ground herbaceous material of a woody plant.
Määritelmä: Of plant duration, a plant whose life span extends over more than two growing seasons, c.f. annual, biennial, ephemeral, of flowering with respect to architecture, hapaxanthic, monocarpic, pleonanthic