Crown of thorns (Euphorbia milii)

Native shrub of Madagascar.Widely cultivated in home gardens as an ornamental. 

Bonpland's croton (Croton bonplandianus)

An introduced woody herb of dry and often sandy open areas in the low country. Native to South America and naturalized in the Sri Lanka.

වැල් කහඹිලියා[Wel kahambiliya] (Tragia plukenetii)

An indigenous twining perennial herb found in the dry lowlands. 

කුප්පමේනිය[Kuppameniya]/Indian copperleaf (Acalypha indica)

Very common native weed found along roadsides, waste lands, cultivation, home gardens etc. Used in Ayurvedic medicine.

බිං දදකිරිය[Bin dadakiriya](Euphorbia thymifolia)

An introduced annual creeping herb. A weed of waste places and cultivated grounds. Also rooting between stones on roadside pavements.

ගස් දුම්මැල්ල/කයිල/වැල් කයිල [Gas dummella/Kaila/Wel Kayila] (Phyllanthus reticulatus)

Common indigenous shrub or small tree occurs in secondary vegetation from sea level to 1000 m altitude. Bark, roots, stem, leaves and fruits are used in medicine.

ගිනි-කැන්ද[Gini-kandha]/Bleeding-heart tree(Homalanthus populifolius)

Probably an introduced tree native to Australia & New Guinea* (Also in Malaysia and Pacific islands) though it was considered as a doubtfully native in Sri Lanka#. It occurs in both primary and secondary forests in the hill country from  1550 m to 2000 m elevations, usually in areas adjacent to tea estates.

* Illustrated field guide to the flowers of Sri Lanka J. & J. de Vlas
# Flora of Ceylon Vol 11 Dasanayaka M.D. & Clayton W.D.*

Croton (Codiaeum variegatum)

Native plant of Indonesia, Malaysia and the western Pacific ocean islands. Introduced and widely cultivated in gardens. There are several hundred cultivars with wide diversity of leaf shapes and colors.

බූ-දද-කීරිය[Bu-Dada-Kiriya]/Common Spurgeof (Euphorbia hirta)

Common introduced weed of waste and cultivated grounds.

Phyllanthus pulcher

Small shrub native to tropical Southeast Asia. Introduced and now an invasive in disturbed rain forest habitats of Kalutara and Ratnapura districts.

Star Gooseberry (Phyllanthus acidus)

An introduced shrub to small tree native to India. Cultivated in home gardens in all climatic zones. Fruits edible.

හීන් කටුපිල [Hin katupila] (Flueggea leucopyrus)

An indigenous shrub occurs in scrublands and thorn-scrubs from sea level up to 150 m a.s.l. Leaves used in medicine. 

Peregrina(Jatropha integerrima[Jatropha pandurifolia])

An introduced shrub or small tree native to Cuba. Cultivated in gardens, Not naturalized.

Copper leaf/Jacob's coat (Acalypha wilkesiana)

Common shrub cultivated in gardens. Native to the Fiji and nearby islands in the South Pacific.

Australian bottle plant (Jatropha podagrica)

Native shrub of tropical America. Cultivated in gardens as an ornamental plant especially in the dry areas of the country due to its drought resistance characteristic.

දලුක් [Dhaluk]/Spurge cactus/Fleshy spurge (Euphorbia antiquorum)

Common indigenous cactus-like shrub or small tree grows on rocky and stony places in the dry lowlands. Whole plant medicinal. 

කැටකෑල[katakela] (Bridelia retusa)

A small tree distributed in dry and intermediate forest subcanopy. Infrequently in wet zone forests also. Roots and barks use in traditional medicine and wood use in construction industry. 

Coral Bush/Coral Plant (Jatropha multifida)

Native herb of Mexico to Brazil. Introduced and cultivated in home gardens, since it is a drought resistant plant with flowers throughout the year.

Red Hot Cat tail/Chenille Plant(Acalypha hispida)

An introduced plant native to New Guinea. cultivated as an ornamental plant in home gardens. 

Mexican fireweed/Lesser green poinsettia (Euphorbia heterophylla)

An introduced very common weed widely distributed throughout the island along roadsides and waste places. It is a native plant of tropical America.