Revised edition (2022) now available:

A Monograph of Euphorbia polygona from the Perspective of an Amateur Botanist

This book is a treatise on Euphorbia polygona, morphologgically perhaps the most diverse member of the genus Euphorbia in the wild. In a way, it is also a plea for recognising and formally labelling natural infraspecific diversity.


Largely guided by field observations between 2010 and 2017, the author identified 12 different natural variations of this South African endemic species, each recognised at varietal level and presented here in detail. The varieties are illustrated by over 200 photographs. Dichotomous identification keys, an infraspecific comparison and a distribution map are also included.


This impressive barrel-shaped succulent spurge is often confused with a cactus and is a very popular garden and greenhouse plant, frequently offered at nurseries in several forms. For those enthusiasts who like to grow Euphorbia polygona, there are cultivation tips and instructions based on the environmental conditions the plants are subjected to in their natural habitat.


Book details: Hardcover, 134 pages (21.5 x 1.5 x 26.5cm), over 200 col. photographs, 3 watercolours by Gerhard Marx, 2 dichotomous identification keys, 1 map and 2 diagrams, English language, ISBN 978-300-058957-7, 40.00 € + postage (add 5.49 € for delivery within Germany or 12.99 € outside Germany, but within the EU). Please write for non-EU rates. 


The book is available from the author through this website's contact form.





Foreword to the Revised Edition

Foreword to the First Edition (2018)



Species of the Euphorbia polygona complex

 Distinct or not distinct?

 Euphorbia polygona: a synonym of Euphorbia cucumerina?

General description of the Euphorbia polygona complex 

Morphological key to the subgroups of the Euphorbia polygona complex

Morphological key to the varieties in the Euphorbia polygona complex

Taxonomic treatment of Euphorbia polygona

The Polygona-subgroup

1.   Euphorbia polygona var. polygona

2.   Euphorbia polygona var. ambigua

3.   Euphorbia polygona var. anoplia

4.   Euphorbia polygona var. exilis

5.   Euphorbia polygona var. nivea (‘Snowflake’)

6.   Euphorbia polygona var. noorsveldensis

7.   Euphorbia polygona var. striata

  The Horrida-subgroup

8.   Euphorbia polygona var. horrida

9.   Euphorbia polygona var. alba

10. Euphorbia polygona var. hebdomadalis

11. Euphorbia polygona var. major

12. Euphorbia polygona var. minor

Euphorbia polygona as a container plant


Annual life cycle

Light exposure

Growth medium



Cold hardiness


Pests and diseases


Appendix 1: Pollinators of Euphorbia polygona 

Appendix 2: Comparison of the varieties of the Euphorbia polygona species complex 

Appendix 3: Distribution map of the Euphorbia polygona species complex 

Appendix 4: Natural hybrids of Euphorbia polygona 

Appendix 5: International Euphorbia Society