Engelhardia is a genus of trees in the family Juglandaceae (the walnut family), placed in the order Fagales. The genus was described by Blume in 1825 (as Engelhardia Lesch. ex Blume), and the GBIF backbone recognizes 31 descendant taxa within it, including species and named varieties.
The genus is native to tropical Asia, ranging from northern India east through southern China and Indochina to Taiwan, Indonesia, and the Philippines. Individual species show more specific ranges within this broader distribution — for example Engelhardia apoensis is native to Malaya, Borneo, and the Philippines, while E. spicata extends from Nepal across southern Asia to the Philippines and New Guinea.
A persistent point of taxonomic trivia surrounds the genus's spelling. Although Blume's original 1825 publication used the spelling "Engelhardia," he himself introduced a "corrected" spelling, "Engelhardtia," in 1829. This altered spelling was subsequently entered into the Index Kewensis and has remained in common use ever since, even though the original spelling, Engelhardia, is the taxonomically correct one.
The genus also has a notable fossil record extending well beyond its current tropical-Asian range. Engelhardia pollen has been recovered from Miocene-age deposits in Denmark, and leaf fossils assigned to the genus (†Engelhardia orsbergensis) have been found in Lower Miocene rhyodacite tuff in southern Slovakia. Further fossils of †E. orsbergensis and †E. macroptera have been described from late Miocene strata in Iceland. Together these finds indicate that Engelhardia, or close relatives, once ranged much more widely across the Northern Hemisphere, including parts of Europe, before contracting to its present tropical Asian distribution.
Distribution
Engelhardia is native to tropical Asia, ranging from northern India east to Taiwan, Indonesia, and the Philippines. Individual species occupy narrower ranges within this — E. apoensis in Malaya, Borneo, and the Philippines; E. spicata from Nepal across southern Asia to the Philippines and New Guinea.
Taxonomy Notes
The genus is properly spelled Engelhardia, per Blume's original 1825 publication, but is commonly seen as "Engelhardtia" — a spelling Blume himself introduced in 1829 and which became entrenched after being used in the Index Kewensis. GBIF's accepted backbone entry uses the original spelling, authored Lesch. ex Blume.
