R. Hand, Supplementary notes to the flora of Cyprus VII. in Willdenowia 41. 2011P. H. Davis, Flora of Turkey and the East Aegean Islands 7. 1982R. D. Meikle, Flora of Cyprus 2. 1985
This new key is mostly based on the key published by Meikle (1985). The treatment of sect. Chamaesyce by Frajman (in Hand 2011) has been integrated. It includes E. humifusa, which has not been found in Cyprus yet but is to be expected. Further testing of the key is required.
1Leaves (mostly) oblique at the base; stipules membranous (in E. graminea sometimes rudimentary); glands appendiculate
1'Leaves symmetrical at the base; stipules membranous, glandular or not; glands ex-appendiculate
2Cyathia in capitate glomerules; ovaries and capsules strigillose
2'Cyathia more lax and not arranged in capitate glomerules; if cyathia dense and nearly globular then plant with glabrous ovaries and capsules
3Plant ascending to erect, up to 0.6 m high; largest leaves usually longer than 15 mm; leaves alternate or opposite
3'Plant mostly prostrate, rarely ascending; the largest leaves usually up to 12(-15) mm long; leaves opposite
4Leaves opposite; cyathia in axial and/or terminal, more or less dense clusters; seeds 0.9-1.3 mm long
4'Leaves alternate, sometimes some opposite; cyathia usually in terminal dichasia, not congested; seeds 1.5-1.7 mm long
5Plant glabrous; stipules membranous, clearly visible, connate; terminal pseudocorymbiform cymes very dense; fruits shorter than 1.4 mm; seeds shorter than 1 mm
5'Plant at least in some parts pubescent; stipules inconspicuous, connate or free; terminal pseudocorymbiform cymes lax; fruits 1.5-2.5 mm long; seeds 1.1-1.3 mm long
6Plant usually glabrous (E. humifusa rarely sparingly hairy); seeds smooth
6'Plant usually pubescent (E. chamaesyce can be glabrous); seeds tuberculate-rugulose or transversely furrowed
7Plant fleshy; leaves falcate-oblong, conspicuously asymmetrical at the base (half of the limb with basal auricle); fruits 3-4 x 4-5 mm; seeds 2.5-3 mm long; plants of sandy coastal areas
7'Plant not fleshy; leaves not conspicuously asymmetrical at the base; fruits 1.2-1.8 mm long and wide; seeds up to 1.3 mm long; plants of ruderal places
8Stems never rooting at nodes; leaves oblong-ovate to oblong-obovate, serrulate at least in upper part, apex rounded; stipules filiform; seeds ovoid
8'Stems often rooting at nodes; leaves ovate to suborbicular, margin entire, apex retuse to emarginate; stipules united into a triangular, laciniate or fimbriate white scale; seeds tetrahedral
9Plant somewhat glaucous; leaves ovate-suborbicular; fruit with patent hairs or glabrous, 1.5-1.9 x 1.6-2 mm; seeds irregularly tuberculate-rugulose, 1-1.4 x (0.6-)0.7-0.9 mm
9'Plant not glaucous; leaves oblong to elliptical or obovate-oblong; fruit appressed-pubescent or hairy only on the keels, 1-1.5(-1.6) x 1-1.5 mm; seeds regularly transversely furrowed, 0.8-1.1 x 0.4-0.6(-0.7) mm
10Leaves on the upper surface mostly with prominent purple spot; stipules linear-lanceolate to filiform, 0.8-1.3 mm long; fruit (all surface) appressed-pubescent
10'Leaves on the upper surface mostly without prominent purple spot; stipules mostly connate at base, triangular-subulate, 0.5-1 mm long; fruit pilose only along the keels
11Stipules membranous, minute; leaves spinulose-denticulate, densely wooly, petiolate; glands pectinate
11'Stipules glandular or not; leaves entire or serrate, variously indumented, usually sessile; glands entire or 2-horned
12Stipules glandular; cyathia with 1-2(-3) glands
12'Plant without stipules; cyathia with 4-5 glands
13Glands rounded on the outer edge
13'Glands truncate, lunate or 2-horned
14Perennial herbs or shrubs
15Plants with a napiform root-tuber; autumn-flowering
15'Plants without a root-tuber; spring- or summer-flowering
16Seeds minutely tuberculate
16'Seeds smooth or shallowly pitted
17A shrub; regma verrucose
17'Perennial herbs; regma smooth
18Stems stiffly erect; cauline- and ray-leaves 1-2 mm wide; seeds pale grey
18'Stems prostrate or decumbent-ascending; cauline- and ray-leaves 2-4 mm wide; seeds brownish
19Seeds smooth
19'Seeds variously ornamented or sculptured
20Leaves finely serrulate; regma beset with subulate processes
20'Leaves coarsely serrate; regma smooth
21Regma villose
21'Regma smooth
22Leaves serrulate; seeds brown, with a flat caruncle
22'Leaves coarsely serrate; seeds black, with a protuberant caruncle
23Annuals; seeds variously ornamented or sculptured
23'Perennials; seeds smooth
24Seeds tuberculate or rugulose
24'Seeds pitted or grooved or both
25Lower cauline leaves densely imbricate, linear-setaceous
25'Lower cauline leaves laxly arranged, linear to linear-oblanceolate
26Cauline leaves petiolate; regma-valves 2-ridged
26'Cauline leaves sessile or subsessile; regma-valves smooth
27Seeds longitudinally grooved and pitted
27'Seeds transversely grooved
28Glands usually long-horned; regma 2.5-3 mm diam.; seeds ovoid, pitted or reticulate
28'Glands short- or medium-horned or almost hornless; regma 1.5 mm diam.; seeds dorsiventrally compressed, transversely grooved or pitted
29Raylet-leaves as long as or longer than broad, lax, with mucro 1-1.5 mm long; seeds 1-2 mm long, with (4-)5-7 transverse grooves per facet
29'Raylet-leaves as broad as or broader than long, densely imbricate, with arista (1-)2-3 mm long; seeds 1.5-2 mm long, with (5-)9-15 transverse grooves or pits per facet
30Regma triquetrous, the valves angled
30'Regma trilobate, the valves rounded
31Plant very fleshy; leaves adaxially concave; caruncle minute
31'Plant not fleshy; leaves flat; caruncle prominent
32Lower cauline leaves more or less equalling the upper; raylet-leaves free
32'Lower cauline leaves much larger than the upper; raylet-leaves connate