Hypericum, Linnaeus, 1753

Robson, Norman K. B., 2016, And then came molecular phylogenetics-Reactions to a monographic study of Hypericum (Hypericaceae), Phytotaxa 255 (3), pp. 181-198 : 181

The Hypericum monograph

My interest in Hypericum Linnaeus (1753: 783) began in 1950, when the British species were the subject of an undergraduate exercise. This was followed by a survey of the genus with a detailed study of its floral anatomy. Knowledge of Hypericum increased through further study and contributions of floristic accounts of it and related genera, so that, by the time (1970) that I started work on a monograph of the genus, I had been studying it for about 20 years. The first part of the monograph ( Robson 1977) was succeeded by eight others, the last part appearing in 2012 ( Robson 2012). In 1970, Hypericum was a genus of over 300 species, a number that has risen today to over 500; so I decided that detailed analytical methods would be too slow to allow completion of the monograph in one lifetime. Instead, I determined to use traditional morpho-geographical methods, i.e. to work with morphological trends, using distribution as a check on their likely validity. It was usually easy to discern such trends and to establish their direction (i.e. polarity), and correlation of such trends provided a further check that they represented a real evolutionary direction. Only when the ‘nearest neighbour’ of a group of related species (e.g. a section) was being sought did it become necessary to make a subjective choice; and then the appropriate taxon was usually apparent.

The monograph was completed in nine parts ( Robson 1977, 1981, 1985, 1987, 1990, 1996, 2001, 2002, 2006, 2010 a, b, 2012, 2015), of which Parts 4 and 5 were divided into respectively 3 and 2 subparts. The original 30 sections were later increased to 36 by dividing sect. 9. Hypericum into sects. 9 and 9a–e, adding 1a. Santomasia and 6a. Umbraculoides and merging section 15. Thasia into 16. Crossophyllum ( Table 1).