Euphorbia lenewtonii Photo by: © Plantemania
Origin and Habitat: Tanzania, Kondoa District.
Habitat and ecology: It is found in soil pockets in rock slabs; at an altitude of around 1225 metres above sea level. It is only known from the type collected in 1993.
Synonyms:
Description: Euphorbia lenewtonii is a densely branching perennial herb, known from only one locality in Tanzania. It has green branches with some yellow highlights and forms tight cushions up to 10 cm tall and 50 cm in diameter, with the lower branches extended at ground level and rooting freely in contact with the soil. In cultivation the stems become more elongate but the plants still are relatively compact. The flowers (cyathia) are yellow.
Derivation of specific name: "lenewtonii" For Prof. Dr. Leonard ("Len") E. Newton (1936-), English botanist at Kumasi University, Ghana, and later professor at the Kenyatta University, Kenya.
Roots: It has thickened roots, to 7 mm in diameter.
Stems: Branches cylindrical, up to 8 cm long amd 1 cm in diameter, with raised tubercle-teeth about1 cm apart in 5 spiral series, green with scattered slightly raised whitish elongated markings. Spine shield crowning the teeth, isolated, oblong-triangular, 3 mm and 1.25 mm wide above the Spines, extending downward to 4 mm, whitish-grey.
Spines: Paired 5-8 mm long. The two stipular spines are shorter, about 2 mm long.
Inflorescences (cymes): Solitary, sessile, 1-forked, with subsessile cyathia.
Flowers (cyathia): Yellow 3 mm long, 2.5 mm wide. Nectar-glands oblong, just touching, yellow.
Fruits: Sessile, hardly 3-lobed, 4 mm across, green at the base, dark red above.
Taxonomy: E. lenewtonii was described by Susan Carter Holmes and published in Cactus and Succulent Journal 72(4): 186-188, ills., 2000. Besides its distinctive habit, it is also distinguished from other more upright members of the Euphorbia tetracanthoides group in its stems bearing 5-spiralled angles rather than being quadrangular in cross section.
Bibliography: Major references and further lectures
1) Urs Eggli, Leonard E. Newton "Etymological Dictionary of Succulent Plant Names" Springer Science & Business Media, 29 June 2013
2) Urs Eggli "Illustrated Handbook of Succulent Plants: Dicotyledons" Volume 2. Springer, 2002
3) International Succulent Introductions of the Huntington Botanical Gardens, ISI 2005-22. Euphorbia lenewtonii Carter, Published in the Cactus and Succulent Journal, Vol. 77 (2), March - April, 2005
4) Euphorbia lenewtonii: In: Conservatorio y Jardin Botanico de Ginebra: Flora africana. Retrieved from http://www.ville-ge.ch/musinfo/bd/cjb/africa/details.php?langue=an&id=106639 on 8 September 2017.
