Table 1 Summary of four white flower species of Androsace umbellata (Lour.) Merr., Bidens pilosa L., Trifolium repens L. and Fragaria × ananassa

Primulaceae

Androsace umbellata (Lour.) Merr.

Corolla regular (salverform or funnel-shaped), white, 4–6 mm broad; petals 5, quite round, touching each other, 4–6 mm in diameter, with a yellow eye. Calyx barely shorter than the corolla,3–4 mm diameter, 5-lobed, green; calyx broadly campanulate to subglobose or hemispheric, not keeled, glabrous, pilose, or puberulent; anthers subsessile. Inflorescence umbels [26]

Widely distributed in the mountains of central Asia, the Caucasus, and the southern and central European mountain systems, particularly the Alps and the Pyrenees. The species and their varieties bear vernacular names based on their characteristics. For example, they are known by such names as Rock Jasmine in English, Dian Dimei in China and Bom Maj I in Korean. They can be found in open grassy areas, roadsides, crops, pastures, gardens, shady places or near streams, ditches or moist embankments

Asteraceae

Bidens pilosa L.

Corolla regular (radiate strap-shaped), white or cream, 5–15 mm broad; 5–8 ray petals, tubular bright yellow or orange disk florets in the center, 3.5–5 mm long. Inflorescence an isolated or grouped pedunculated capitula, emerging from the leaf axil [2]

It is thought to originate in South America and subsequently spread all over the world. The species and their varieties bear vernacular names based on their characteristics. For example, the species are known by such names as Spanish needles, Beggar’s ticks, Devil’s needles, Cobbler’s pegs, Broom stick and Pitchforks in English and some other languages because of their sticky achenes and are sometimes known as Xian Fengcao (“all bountiful grass”) in Chinese because of their prosperous growth. They can invade roadsides, crops, pastures, gardens, disturbed areas, fallow lands and urban open space

Fabaceae

Trifolium repens L.

Corolla zygomorphic, white (sometimes slightly reddish), later brownish, 8–10 mm long, fused at base. Petals 5; the upstanding the ‘standard’, the lateral two the ‘wings’, the lower two united to form the ‘keel’, overall shape of corolla being butterfly-like. Calyx 5-lobed, glabrous. Stamens 10. A single carpel. Inflorescence a long-stalked, densely globose head, flowers fragrant [31]

Native to Europe and central Asia and has become one of the most widely distributed legumes in the world. The species are sometimes known as the White clover, Dutch clover and Ladino clover. The species thrive best in a cool, moist climate in soils with ample lime, phosphate, and potash. In general, it is best adapted to clay and silt soils in humid and irrigated areas. It grows successfully on sandy soils with a high-water table or irrigated droughty soils when adequately fertilized

Rosaceae

Fragaria × ananassa

Corolla regular (actinomorphic), white, 12–18 mm broad; petals 5, quite round, touching each other or covering edges of each other, 4–6 mm long. Calyx 5-lobed; with epicalyx. Stamens 20. Gynoecium separate, pistils several. Receptacle glabrous. Inflorescence a lax cyme [1]

Firstly bred via a cross of Fragaria virginiana from eastern North America and Fragaria chiloensis from Chile. The species are sometimes known as the Garden strawberry, Fraisier des bois. The species is cultivated worldwide for its fruit. The habitat is along trails, roadsides, embankments, hillsides, stone- and gravel-laid paths and roads, meadows, young woodlands, sparse forest, woodland edges and clearings