1	"Plants herbs with fleshy,  often swollen stems"	2
1	"Plants shrubs or trees with woody or semi-succulent branches"	9
2	"Cyathia with 4 glands each"	3
2	"Cyathia with 1 or 2 glands each"	5
3	"Cyathial glands glabrous"	"Euphorbia systyla"
3	"Cyathial glands pubescent on margins and outer surfaces"	4
4	"Stem branched, sometimes swollen at the bae but always < 10 mm thick;  plants 15-60 cm tall"	"Euphorbia acalyphoides"
4	"Stems unbranched,  10-20 mm thick;  plants 4-10 cm tall"	"Euphorbia hadramautica"
5	"Inflorescences 15-30 cm long;  leaves 2-6 cm long, linear-lanceolate; cyathia with 2 glands each"	6
5	"Inflorescences 3-5 cm long;  leaves 1-1.5 cm long, ovate; cyathia with 1 gland each"	7
6	"Stems with prominent leaf-scars but without projecting tubercles;  bracts 5-8 mm long, ovate"	"Euphorbia etuberculosa"
6	"Stems with conspicuously projecting tubercles;  bracts at least 10 mm long, leaf-like"	"Euphorbia longituberculosa"
7	"Stems globose, 2-3 cm in diameter;  roots tapering, up to 5 mm thick"	"Euphorbia globulicaulis"
7	"Stems cylindrical, 0.5-2.5 cm in diameter;  roots tuberous, as thick as the stems"	8
8	"Tubercles not overlapping;  seeds about 2 long and 1.5 mm wide"	"Euphorbia scyphadenia"
8	"Tubercles overlapping on basal branches;  seeds about 3 and 2.5 mm wide"	"Euphorbia adenochila"
9	"Cymes umbellate with dichotomously branching rays;  cyathial glands pectinate on outer margins"	10
9	"Cymes reduced to single cyathium or umbels with simple (rarely branching) rays;  cyathial glands with entire outer margins or, if lobed or pectinate, rays of umbel simple"	11
10	"Bracts green;  processes on outer margins of cyathial glands 2-4 mm long"	"Euphorbia noxia"
10	"Bracts red;  processes on outer margins of cyathial glands < 1 mm long"	"Euphorbia thulinii"
11	"Glandular stipules absent;  bracts similar to leaves"	"Euphorbia balsamifera"
11	"Glandular stipules present, often minute;  bracts always evidently distinct different from the leaves, sometimes scale-like, sometimes conspicuous and creamy-white"	12
12	"Outer margins of cyathial glands distinctly pectinate"	13
12	"Outer margins of cyathial glands entire or minutely crenulate"	18
13	"Cyathia 4-5 mm in diametrer;  capsules about 6 mm in diameter"	"Euphorbia gypsophila"
13	"Cyathia 10-15 mm in diameter;  capsules at least 13 mm in diameter"	14
14	"Capsules smooth, without wings,  ridges, or projections"	15
14	"14;Capsule ornamented with additional fleshy wings;  longitudinal ridges or projections;16;"	16
15	"Mature leaves and capsules glabrous"	"Euphorbia nogalensis"
15	"Mature leaves and capsules pubescent"	"Euphorbia kiritensis"
16	"Outer margins of cyathial glands with 5-10 finger-like processes ± 1 mm long, each with with minutely bifid tips;  capsules with winged ridges"	"Euphorbia giumboensis"
16	"Outer margins of cyathial glands with 2-7 finger-like processes 1-3.5 mm long each divided into 2-6 knobs at tips;  capsule without wings on ridges"	17
17	"Lower surfaces of leaves glabrous or almost so;  umbels with 2 to 3 rays, these 0.8-1 cm long"	"Euphorbia appendiculata"
17	"Lower surfaces of leaves pubescent;  umbels with 3 to 6 rays, these 1-1.5 cm long;;"	"Euphorbia carinulata"
18	"Ovaries exserted on reflexed pedicels, glabrous with deeply corrugated surfaces"	"Euphorbia leucochlamys"
18	"Ovariel or nearly so, usually pubescent, with with smooth surfaces"	19
19	"Outer margins of cyathial glands minutely crenulate;  capsules ± 15 mm in diameter"	"Euphorbia grosseri"
19	"Outer margins of cyathial glands entire;  capsules 3.5-8 mm diam.;20;"	20
20	"Leaves > 3 cm long;  bracts conspicuous and white or slightly yellow"	21
20	"Leaves at most 2.5 cm long;  bracts similar to or much smaller than leaves and not differently coloured"	22
21	"Leaves oblanceolate to panduriform;  cyathia ± 10 mm in diameter"	"Euphorbia jatrophoides"
21	"Leaves linear;  cyathia ± 6 mm in diameter"	"Euphorbia kelleri"
22	"Plants shrublets, up to 0.3 m tall"	23
22	"Plants shrubs or small trees 0.5-4 m tall;"	24
23	"Branches erect and densely rebranched;  leaves oblanceolate, 10-18 mm long"	"Euphorbia intricata"
23	"Branches horizontally spreading with branchlets at right angles;  leaves obovate, 5-8 mm long;"	"Euphorbia dunensis"
24	"Branches alternating or in opposite pairs"	"Euphorbia cuneata"
24	"Branches often in groups of three"	"Euphorbia tripartita"