Small inflorescence, big discovery: Dalechampia parvopseudantha (Euphorbiaceae), a new species from the Brazilian Atlantic Forest

Summary Dalechampia parvopseudantha (Euphorbiaceae), a new species with the smallest pseudanthium (2 – 2.5 cm long) within Dalechampia sect. Tiliifoliae , is described from the Atlantic Forest of Espírito Santo state in southeastern Brazil. The species is further distinguished by a combination of a 5 – 6 mm long peduncle; involucral bracts 1 – 1.5 × 0.7 – 0.8 cm, slightly 3-lobed, oblanceolate, yellowish-green, with a tomentose surface; staminate flowers with three broadly lanceolate sepals; sepals of pistillate flowers bearing conspicuous glandular trichomes and a stylar column with a slightly lobed apex. This unique set of morphological features readily distinguishes D. parvopseudantha from all other species of Dalechampia sect. Tiliifoliae , which is widely known to bear relatively large, up to 6.5 cm long pseudanthium. A full description, illustrations, field photographs, distribution map, phenology, habitat and a preliminary conservation status assessment are provided, as well as a table comparing the new species with its morphologically related, congeneric species. The striking size reduction of the pseudanthium discovered in a genus long used as a model for pollination biology, suggests that key ecologically informative variation may remain undocumented even in comparatively well-studied lineages.