Monday, 14 November 2016

Cashew cousins

In a blog recently ('Spines and Cyanide', 23 October) I made mention of the Cashew Nut Family, Anacardiaceae. Strolling through Daventry earlier today I had reason to think a little further about this largish family of close on 900 species spread across about 90-95 genera. I suppose that it is in many ways  group of plants with a low profile in the U.K., unsurprising really since no members of the family are native to this country. The only species we are likely to come across are members of the genera Rhus and Cotinus. So why did they come to mind on my walk? Quite simply, they take on such striking autumnal colours.
Stag's Horn Sumach in Christchurch Drive, Daventry. 13 November, 2016
Most people know the Stag's Horn Sumach, Rhus hirta (= Rhus typhina). It is largely planted for its large, graceful, pinnately-compound leaves but also for the rather furry, curiously thick twigs, fancifully resembling the horns of a Red Deer when 'in velvet'. The leaves, at this time of the year, are very eye-catching, as shown below.
The same plant in close-up.

The flowers are nothing to get excited about, even if they form a rather unusual stiff inflorescence.
The curious inflorescence of Stag's Horn Sumach.
Northampton. 15 November, 2016
This species rarely produces seed in the U.K. but this hasn't stopped it from regularly escaping from gardens via an extensive suckering system. It may pop up, disconcertingly, in the middle of an otherwise immaculate lawn.


The Smoke Bush, Cotinus coggyria, is equally familiar to gardeners. It was once known as Rhus cotinus, the name given to it by Linnaeus, but it has significant differences, most notably in the form of the leaves. These are simple as opposed to pinnate but like the Stag's Horn Sumach, it assumes rich autumn colours. However, the form most commonly grown in gardens has distinctive purple leaves throughout the growing season and is generally marketed as 'Royal Purple'. It does produce seeds and the occasional seedling is found but nowhere has it become established in the wild.  These shrubs are related to the Poison Ivy species, such as Toxocodendron radicans, of North America but the family includes some surprising edible plants.
Smoke Bush, London Road, Daventry. 13 November, 2016
One is the Cashew Nut, Anacardium occidentale and another popular nut is the Pistachio, Pistacia vera. And finally there is the Mango, Mangifera indica, a fruit known to have been eaten in India as far back as 5,000 years ago.


I frequently find other members of the family when on Mediterranean holidays and the flowers are invariably dull, but this factor is compensated by attractive foliage and I notice that a bunch of flowers in our dining room includes a sprig of the Mastic Tree, Pistacia lentiscus.
Pistacia lentiscus provides foliage interest in a bunch of
flowers. Daventry, 14 November, 2016
With climate warming other Anacardiads may find their way into our gardens.





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