Mecardonia

They are herbaceous procumbent glabrous plants. They are mostly blackened when they are dry. Their stems are 5–40 cm in length and they have 4-alate leaves. Ovate leaves 7–25 mm in length and 3–16 mm wide, with a crenate edge; petiolate. Solitary axillary flowers, pedicles 8-20 (-26) mm in length, basally bibracteolate; 5-lobed calyx, with unequal lobes, more or less free to the base, imbricate, the adaxial lobe widely lanceate to ovate, 5–9.5 mm long and 3–6 mm wide, slightly accrescent, the 2 middle lobes longer and overlapping, the 2 abaxial lobes nearly the same size as the adaxial and overlapping the middle lobes; 5-lobed corolla, 7–8 mm long, yellow with purple at the throat, bearded at the mouth; 4 fertile stamens. Ovoid fruit capsule, 5–7 mm long, loculicidal; ovoid, reticulated seeds.^[12]

The genus was described by Ruiz & Pav., published in Florae Peruvianae, et Chilensis Prodromus 95. 1794. ^[12][13] The type species is: Mecardonia procumbens Ruiz & Pav. The genus is named after Antonio Meca y Cardona, who founded the botanical gardens in Barcelona, in 1784.^{[14][15] [16]}

Rossow (1987) in his taxonomic revision of the genus, recognized ten species. A new species, M kamogawae, was identified in Argentina by Greppi and Hagiwara (2011).

Sold as an ornamental garden flower, such as Mecardonia Magic Carpet Yellow, as annuals in colder areas.

• Mecardonia acuminata (Walter) Small.
  • Mecardonia acuminata acuminata^[11]
  • Mecardonia acuminata peninsularis^[11]
  • Mecardonia acuminata microphylla.^[11]
• Mecardonia berroi Marchesi
• Mecardonia caespitosa (Cham.) Pennell
• Mecardonia exilis (Brandegee) Pennell
• Mecardonia flagellaris (Cham. & Schltdl.) Rossow
• Mecardonia grandiflora (Benth.) Pennell
• Mecardonia herniarioides (Cham.) Pennell
• Mecardonia procumbens (Mill.) Small
• Mecardonia pubescens Rossow
• Mecardonia serpylloides (Cham. & Schltdl.) Pennell
• Mecardonia tenella (Cham. & Schltdl.) Pennell