Skip to content
Cactuswiki open cactus and succulent encyclopedia.

Euphorbia guillauminiana Boiteau

Family: EUPHORBIACEAE

Publication: Bull. Trimestriel Acad. Malgache n.s., 24: 87 1942.

Description

Euphorbia guillauminiana is a densely branched, hemispherical, succulent-stemmed shrub, up to 60(-100) m high, wit thick, branches with spines arranged in 8 rows, numerous towards the apex. The leaves are crowded at the apices of the stems. The flowers are yellow or red.

Stem: Trunk thick, branching at 10 cm high, rebranching at intervals in 3 to5 smaller

branchlets; branches are numerous thick, horizontally spreading, grey, cylindrical 1-1.5 cm in diameter.

Leaves: Sessile or short petioled, rosulately crowded at branches tips, ovate, to 2 cm long, and 1 cm broad, dark green, glabrous, glossy, with a definite central rib, leaf margin pink or white. Petiole to 8 mm long, thick. Deciduous.

Stipular spines: 2-4 at each node, numerous towards the apex in 6-8 rows, slightly spreading, 12-30 mm long, base expanded, grey with age, deciduous.

Inflorescences. Cymes at branches tips, 1- to 2-forked, subsessile, peduncles short, with 2 to 4 cyathia, these erect. Cyathophylls (leaf-like bracts surronding the flowers) erect, completely enclosing the cyathium, yellowish green or yellow, rarely red, enveloping the ciathia.

***Flowers (Ciathia): ca. 2.5 mm in diameter, hairy. Nectar-gland yellowish. Ovary hairy.

Origin and Habitat

Euphorbia guillauminiana is endemic to the District of Analalava (Ambarijeby, Boriziny): Port-Bergé area in Westerm Madagascar. This species has a small area of occupancy (96.1 km²).

Habitat and ecology: This species grows on basalt rocks. It is threatened by habitat degradation and human activity, as well as by illegal collection for the horticultural trade.

Cultivation and Propagation

Euphorbia guillauminiana is quite difficult to cultivate, and extremely sensitive to watering while dormant. Best kept by continuously growing new seedlings to replace losses.

Bibliography

Major references and further lectures

  1. Hermann Jacobsen, “Abromeitiella to Euphorbia”, Blandford Press, 1960

  2. Hermann Jacobsen, “A Handbook of Succulent Plants: Descriptions, Synonyms, and Cultural Details for Succulents Other Than Cactaceae”, Volume 1, Blandford Press, 1960

  3. Urs Eggli, “Illustrated Handbook of Succulent Plants: Dicotyledons”, Volume 2. Springer, 2002

  4. Haevermans, T. 2004. Euphorbia guillauminiana. The IUCN Red List of Threatened Species 2004: e.T44357A10895639. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T44357A10895639.en. Downloaded on 19 November 2017.

  5. Walter Minuth, Rikus van Veldhuisen & Volker Buddensiek, “Euphorbias from A – Z”, Vol. 7 n. 1 - April 2011(pp.27-27)