Archive | August, 2015

Following the primrose path- why early botanists may have not dallied long enough to understand the secrets of heterostyly



This week (August 10th 2015) saw the launch of Professor Phil Gilmartin’s beautifully illustrated article ‘On the origins of observations of Heterostyly in Primula’ in the journal New Phytologist. Professor Gilmartin, Visiting Professor at the John Innes Centre and Dean of Science at UEA’s School of Biological Sciences, owes his interest in the history of heterostyly to the fact that he collects and loves old botanical prints. One day while studying the illustrations of William Curtis’s Flora Londiniensis, an eighteenth century publication documenting the wild plants growing within a 10 mile radius of London, and one that brought Curtis ‘praise’ rather than ‘pudding’, Gilmartin noticed that Curtis had drawn both of the two types of flower that occur in Primula. The phenomenon Curtis illustrated is called heterostyly – flower forms where the styles of the plants are of two (and sometimes three) distinct forms: long- or short-styled. If the style with its stigma (or pin) reaches the top of the tube part of the flower, the flower is ‘long-styled’. The stamens either form a ring at the top of the tube or about halfway down its interior. The flower is described as ‘short-styled’ where the stigma reaches only about halfway up the tube and the stamens are situated above it. [For further explanation see this infographic video about heterostyly at ]

In plant science this observation is usually associated with Charles Darwin who made a series of painstaking experiments on the two forms of flower in Primula in the 1860s, work that sparked a major research project for Darwin that was ultimately published in two books: The Effects of Cross and Self Fertilisation (1876) and Forms of Flowers (1877). Darwin did not coin the term ‘heterostyly’ (this term originates with German botanist Friedrich Hildebrand) but he was one of the first to attempt to understand its reproductive significance. Professor Gilmartin’s surprise encounter with an 18th century depiction of heterostyly, 70 years before Darwin’s observations, led him to ‘follow the primrose path’ through archives, rare books, letters, prints and botanical paintings. The results of his investigation, revealed in fascinating detail in his new article, show that at least seven botanists either drew or described the two forms of flower before Darwin made his observations- the earliest going back to the 16th century.


Auricula engraving, 1615

Crispin van de Pas’s Auricula engravings in Hortus Floridus (1615)


This all begs the question- if the existence of two forms of flower in Primula was such common knowledge, why didn’t botanists study the subject more fully before Darwin? This blog offers some possible explanations, grounded in social history. Before Darwin, the two forms of flower were commonly known as ‘pin’ or ‘pin-eyed’ (long-styled) and ‘thrum’ or ‘thrum-eyed’ (short-styled). This vocabulary comes from the ‘Florist’ rather than botanical tradition, a language with which Darwin was not familiar- in his early letters on the topic he repeatedly referred to ‘thumb-eyed’ forms, missing its etymology completely. By the time his books were published Darwin had done his research and quoted Johnson’s dictionary to explain the origin of the correct term: ‘Thrum is said to be the ends of weaver’s threads, and I suppose that some weaver who cultivated the polyanthus invented this name, from being struck with some degree of resemblance between the cluster of anthers in the mouth of the corolla and the ends of the threads’. (Forms of Flowers, 1877, p.14).

This quotation accurately situates knowledge of the different forms of flowers to the ‘Florists who cultivate the Polyanthus and the Auricula’. The word ‘Florist’ connoted a very specific social world, an artisanal tradition rooted in the hand-loom and home-working weaver communities of Norwich, London, Lancashire and Yorkshire. This tradition is often located to the arrival of Huguenot Flemish weavers fleeing religious persecution and settling in England in the 1570s, bringing their favourite plants with them and their specialist skills in flower cultivation. By 1623, when the word ‘Florist’ was first used in print, a group identity for these flower enthusiasts was established. ‘Florists’ were skilled hobbyist growers (the modern sense of the flower-selling Florist does not appear until the late 19th century). In Norwich, to use a local example, there is evidence that ‘Florists’ Feasts’ were being held from 1631: these were social gatherings held in the City’s pubs where flower expertise was displayed in competitions and celebrated. The first newspaper advert for a ‘Florists’ Feast’ appeared in the Norwich Gazette in 1707. Dr Sam George has documented the growth of the feast tradition all over England and into Scotland by the late 18th century, by which time ‘Florists’ Flowers’ connoted a very specific group of non-native plants including tulips, auriculas, primulas and carnations. For example, the Paisley Florist Society (founded 1768), whose members were weavers, were famous for their carnations (‘Paisley Pinks’), while Lancashire silk weavers were renowned for their show Auriculas.

Auricula varieties, 1736-1748

Auricula varieties, hand coloured illustration from J W Weinmann, Duidelyke vertoning (1736-1748)

By the 18th century, when Curtis was writing, it had become habitual to distinguish the work of the ‘botanic philosopher’ from that of the ‘fashionable florist’. The very flowers that held the fascination of Florists were objected to as ‘foreign’ monsters, perverted perhaps from their natural form by ‘vulgar’ and ‘unnatural’ methods of raising plants for flower ‘improvement’. Scholars of botany distinguished themselves as students of natural species and naturally occurring hybrids, while a new patriotic emphasis on native flora also played in to the botanists’ disregard of the more showy florists’ flowers. Curtis, for example, invoked the authority of Linnaeus to make this distinction: ‘Linnaeus indeed cautions Botanists against being seduced by the gaudy tints that fascinate the mere Florist’. Working class and women botanists of the 19th century, both groups who were at times co-opted and at others marginalized by the mainstream male botanical tradition, also adopted these distinctions to clearly differentiate their studies from the disapproval meted out to ‘florists’ who in the standard narrative were synonymous with superficial observers. In truth, the Florists’ observation of their flowers was anything but superficial. As Roland Biffen pointed out in his monograph on the Auricula: ‘at an early stage of their work they defined the ‘properties’ which they considered the perfect flower should possess’. One of these points was that flowers should be thrum-eyed, because ‘the pin-eyed flower shows a chasm or vacancy very unpleasant to the eye of the curious florist’ (quoted in Biffen 1951, p. 15). Rules established for judging flower perfection at competitions were adhered to rigidly. Points that were of fundamental importance to the Florists, however, were of no interest to botanical science. Botanists prided themselves (in rhetoric at least) on not making aesthetic judgments about flowers, and the attention to variations in individual plants (so important a skill in genetics) was part of the ‘noise’ from which the botanist had to avoid being distracted, rather than the ‘signal’ (which in their world view was the essential character of the species).

Primula varieties, 18th century

Primula varieties (ibid.) showing the popularity of these Florists’ flowers in the 18th century

If heterostyly had only occurred in foreign Florists’ flowers it would perhaps have been overlooked altogether in scholarly botanical works. However, Curtis made the observation in native ‘Primula acaulis’ (common primrose). But situated as the phenomenon was in the Florists’ world worked against it being taken as a topic of serious study. Curtis side-lined the observation from further scientific investigation with the comment ‘We are then asked to marvel at the inventiveness of God: we are permitted to gratify our sight with the endless varieties the flowers put on, when cultivated by the curious’. Linnaean botany with its emphasis on taxonomy, collections, local floras and plant distributions was focused on establishing ‘type’ descriptions and specimens. Variation in individual flower form within a species was a nuisance for classifiers rather than a problem to be solved. Linnaeus, Curtis and the 18th and 19th century botanists that followed were fixated on a different problem, namely the specific differences between the primrose, the cowslip and the oxlip. As Curtis commented ‘Who is there that does not know the Primrose, the Cowslip, and the Oxlip? The differences between which even a child would be ashamed to be told that it was unacquainted with: and yet to this hour it is a question among the most learned Botanists if they are really distinct species’- a question that continued to fascinate in Darwin’s day.

To paraphrase Sam George- the opposition of botany to ‘Florists’ was shot through with tensions of class and nation. Fancy foreign flowers, artisan knowledge, and alien vocabulary all hampered the transfer of knowledge between the social worlds of the Florists and the ‘philosophic botanists’. That the Florists exchanged their expertise in the pub was also to risk disapproval within contemporary ideas of respectability, a problem Anne Secord has illuminated in detail in her thought-provoking study of artisan botanists in Lancashire. Anne uses tools from social science to explain that botanical specimens and Linnaean nomenclature were ‘boundary objects’ that could have different meanings for participants of distinct social groups and yet allow communication (or ‘translation’) between these different social worlds. Unfortunately for the study of heterostyly, ‘pin’ and ‘thrum-eyed’ flowers did not fit into this Linnaean model of exchange but remained part of the culture of the flower shows. Until Darwin’s studies, early botanists would not go down this particular primrose path which at the time would seem to be a diversion rather than a way of illuminating flower development or plant reproduction.

Further reading:

(All quotes in the blog are from the editions cited here – the rare books illustrations and Darwin volumes are available to view by appointment in the John Innes Historical Collections)

Roland H. Biffen, The Auricula: the story of a Florists’s Flower (Cambridge University Press, 1951). This study has recently been reprinted by CUP.

William Curtis, Flora Londiniensis. New edition revised and enlarged by George Graves and W J Hooker (London, 1835); Vol IV, Primula acaulis and Primula elatior. This edition was published after Curtis’s death. He started this multi-volume work in 1777 but by 1787 his project foundered.

Charles Darwin, ‘On the two forms or dimorphic condition in the species of Primula, Journal of the Proceedings of the Linnean Society, 6 (1862), p. 77.

Charles Darwin, The Effects of Cross and Self Fertilisation in the Vegetable Kingdom (London, John Murray, 1876).

 Charles Darwin, The Different Forms of Flowers on Plants of the Same Species (London, John Murray, 1877).

 Sam George, Botany, Sexuality and Women’s Writing, 1760-1830: from modest shoot to forward plant (Manchester University Press, 2007).

Phil Gilmartin, ‘On the origins of observations of heterostyly in Primula, New Phytologist, first published online on 10th August 2015.

Anne Secord, ‘Science in the Pub: Artisan Botanists in Early Nineteenth-century Lancashire’, History of Science, 32 (1994): 269-315.


For more information about Phil Gilmartin’s paper email

Professor Gilmartin is Visiting Professor in the Department of Cell and Developmental Biology at the John Innes Centre. He is Dean of Science at the University of East Anglia and his research lab is based at JIC where he studies plant development, gene regulation, sex determination in plants and heteromorphy.

To book an appointment to visit the John Innes Historical Collections email


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