Origin and Habitat: Euphorbia greenwayiSN|35284]]SN|35284]] subsp. greenwayi is known from a single location in the Iringa Escarpment, Tanzania. Estimated area of occupancy (AOO) 3 km2
Type locality: Iringa District: Iringa Escarpment f 65 km. N. of Iringa on Dodoma road.
Altitude range: 1000-1250 metres above sea level.
Habitat: Miombo woodland. This species grows in rocky outcrops with Brachystegia open woodland. The habitat quality is declining due to harvesting of woodland products near Iringa town: firewood, charcoal (which impacts the whole habitat) and the digging up of plants. Due to single location and ongoing threat, this taxon is assessed as Critically Endangered.

• Euphorbia greenwayi P.R.O.Bally & S.Carter

Description: Euphorbia greenwayiSN|35284]]SN|35284]] (subsp. greenwayi) is a basally branching succulent perennial to 30 m high with attractively marbled stems that trail along the ground without rooting . The four-sided branches are markedly variegated with vertical rainbow striations fading from green to blue to whitish grey along the prominently and sharply-toothed spined margins outlined in reddish brown. Spines thin 8-10 mm long. Unusual pinkish flowers in spring with long, thin red stigma lobes beautify the plant. Two subspecies are recognized, the nominate form and var. breviaculeata which forms a taller, more erect shrub to 1.2 m tall with shorter spines 5-8 mm long
Stem (branches): Short, spreading from the base, sharply 4-angled, blue-green to whitish grey markedly variegated with darker blotches along the prominently and sharply-toothed angles, and with shallow to prominent teeth to 1 cm apart.
Spine-shields: Elongated to 2 x 1 mm above the spines, extending downward to the flowering eye below and often forming a continuous horny margin.
Spines: Slender 8-10 mm long, red becoming black as they age. Prickles 3-5 mm long.
Leaves: Acutely triangular, 1.5 long, 1 mm broad.
Inflorescence (cyme): solitary, 1-forked, with peduncles and cyme-branches to 5 mm long. Bracts ovate, about 1.5 mm long 1.25 mm broad.
Flowers (cyathia): Up to 3 mm long and 4.5 mm in diameter, with cup-shaped involucres. Nectary-glands transversely rectangular, ca. 1 x 2 mm broad, not quite touching; lobes rounded, 1 mm long and wide.
Male flowers: Few; bracteoles spathulate, deeply toothed. Stamens 4.5 mm long.
Female flower: Styles 3 up to 3.5 mm long, joined for 1.5 mm, red, apices slightly thickened.

Bibliography: Major references and further lectures
1) Urs Eggli "Illustrated Handbook of Succulent Plants: Dicotyledons" Volume 2. Springer, 2002
2) Susan Carter, A. R. Smith “Flora of Tropical East Africa - Euphorbiac v2” CRC Press, 1 June 1988
3) IUCN SSC East African Plants Red List Authority. 2013. Euphorbia greenwayi var. greenwayi. The IUCN Red List of Threatened Species 2013: e.T47348564A47348567. http://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T47348564A47348567.en. Downloaded on 01 July 2018.
4) Euphorbia greenwayi in: “The Euphorbia Journal” Strawberry Press, 1994