The cosmopolitan Compositae (or Sunflowers at large…)

Sunflowers by Stephen Harris 2018. Reaktion Books Ltd.

Stephen Harris’ Sunflowers isn’t about sunflowers. OK, correction, it is, but it’s not just about sunflowers. Rather, the book celebrates the sunflower family, the Asteraceae (or what those of a certain botanical background know more affectionately as the Compositae). And, why not? With approx. 32,000* species it’s one of the biggest assemblages of flowering plants on the planet, and is therefore a family worthy of celebration. And celebrate that amazing family is what Harris does in this remarkable book.

Sunflowers is one of the growing collection of titles in the publisher’s – Reaktion Books – Botanical series, which is the “first series of its kind, integrating horticultural and botanical writing with a broader account of the cultural and social impact of trees, plants and flowers”. Sunflowers certainly achieves the series’ goal. In doing so, Harris shares lots of interesting things, and Sunflowers is a creditable – and credible – compilation of Compositae ‘collectabilia’. For example, you’ll: discover the name of those who study the Asteraceae **; find out that the Asteraceae were around when the dinosaurs roamed the Earth (but, whether those beasts ever stopped to smell the flowers we probably won’t know); learn that seeds are essentially “buds that move”; be surprised to find out that pseudocopulation is practised by some asteraceans (so this plant-reproductive strategy is not the preserve of orchids); be reminded of the importance of sunflowers to Stephen Hales’ early-18^th century, pioneering investigations into transpiration; be introduced to the notion that ecologically fire can be viewed as ‘chemical gazing’; learn that the soporific properties of lettuce were used as a plot device by Beatrix Potter (although, given that it’s rabbits she wrote about in this context, one could have forgiven her for considering that salad vegetable’s more aphrodisiac associations [also covered by Harris…] as far as those famously fecund and furry mammals are concerned…); find out that Jerusalem artichoke is also known as Canadian potatoes; be amused to find out that the thistle genus Onopordum means ‘donkey fart’; and hear that edelweiss was allegedly the favourite flower of one Adolf Hitler (with that knowledge you might see the Sound of Music in a new light, and no longer be as keen to sing-along to Edelweiss….).

But, there’s a lot more to Sunflowers than those items of ‘trivia’, you’ll just have to find that out for yourselves. And pleasingly, knowing how keen Harris is to ensure that facts are verified (Harris, Current Biology 28(9): R530–R532, 2018; https://doi.org/10.1016/j.cub.2018.03.029), the book gives you the opportunity to follow-up most of those in-text statements with the original sources. However, there were occasional lapses. For instance, I’m keen to have sources for the statement that the spongy trunks of some Andean frailejóns capture water and release it into the soil (p. 74), and the intriguing notion that recent spread of ragweed may be related to the fall of the Berlin Wall (p. 98). I also wonder whether there is a little confusion over C4 photosynthesis (more commonly associated with non-asteraceans such as sugar cane and maize, but also found in composites such as Flaveria) and crassulacean acid metabolism (CAM, famously found in members of the Crassulaceae and Cactaceae). Why? Because Harris states that CO₂ is ‘converted’ to 4-carbon atom molecules in special cells, but – and incorrectly as far as I’m aware – at night in C4 photosynthesis (p. 76). Correctly, Harris does also talk of nocturnal carbon-acquisition via the open stomata of CAM plants (p. 76). Generally, Sunflowers is a fine read, and an enjoyable one; occasionally, however, it gave cause for pause as one wondered what certain words meant. For example I haven’t yet looked up ‘soteriological’ *** (p. 161), or discovered what a universal ‘theriac’ *** (p. 163) is. Nevertheless, I don’t believe my particular etymological ignorance spoilt my enjoyment of the book. But these are relatively minor quibbles; whichever way you look at it, Sunflowers is certainly informative and educational (and will extend your word power…).

I teach an undergraduate module whose major assignment is the production of an article in which the students argue for a particular flowering plant family being the most important.  I‘m therefore in two minds as to whether I should make this book known to my students. On the one hand they might be tempted just to use Harris’ tome if they choose to ‘big-up’ the Asteraceae (although they are aware of the perils and penalties associated with over-reliance on a single reference in scientific writing…). On the other, Sunflowers should be seen as a great example – an inspiration even – of what’s possible for that assignment. Dilemma over; there’s no contest, Sunflowers goes straight on to the module’s reading list for 2018/19! Indeed, along with Harris’ Reaktion Botanical series tome Grasses, and his Bodleian book entitled What Have Plants Ever Done for Us?, you’ve got almost an entire plants-and-people module in three – very affordable! – books…

Summary

Stephen Harris’ Sunflowers is a great example of what can be achieved with ‘snatched hours here-and-there outside of the day job‘ (although it is acknowledged that the material for the book was accumulated over 30 years…). Sunflowers is a great book, which I recommend to any- and everybody who wants to know a little – or even a lot! – more about the plant-and-people aspects of the mighty sunflower family (or get extra information for coursework…).

* Maybe I missed the citation in the book, but I would like to know where that value comes from. The biggest numbers I found were 25,000 in Mabberley’s Plant-Book, 4th Edition, 2017 (listed under Compositae…), and 24,700 in Christenhusz et al., Plants of the World, 2017.

** To avoid having to issue a ‘spoiler alert’ in-text, such a person is a synantherologist.

*** I have now; Soteriology is “theology dealing with salvation especially as effected by Jesus Christ”, and theriac was an ancient ‘wonder-drug’.