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，被大多数植认为是变种的色和红色 pimpernel，Gartner 认为非常不育， 因此他将它们列为无可置疑的种。