Splitters versus lumpers

Roses also attracted the attention of botanists. Due to their variability and the often ill-defined boundaries between species, Carl Linnaeus (1707-1778) - the Swedish botanist who formalised the modern system of naming organisms - only poorly understood their identity, affinities and classification.

During the 19th century, a growing number of European botanists keen on solving the riddle developed a special interest in roses. Most of these rhodologists (from the Greek rhodon, rose) initially concentrated on the study of collections from their home region, but some expanded their outlook to include plants from the whole natural range of roses, which grow only in the northern hemisphere.

European botanists discovered that roses showed a remarkably wide range of variations, which made naming and classifying them a demanding task. Botanists adopted two contrasting approaches. The splitters interpreted each slight variation in the materials they studied as sufficient reason to create a separate species, and thus they described thousands of new roses. The lumpers accepted much more variation within species and were less inclined to create new species. Sorting their piles of herbarium specimens, the lumpers concentrated on finding meaningful common traits instead of insignificant differences and, as a result, identified a much-reduced number of species.