For instance, the blue and red pimpernel, which are considered by most botanists as varieties, are said by Gartner to be quite sterile when crossed, and he consequently ranks them as undoubted species.

例如，被大多数植物是变种的色和红色 pimpernel，Gartner 后非常不育， 因此他将它们列无可置疑的物种。