1. Mitrastemon Makino, Bot. Mag. (Tokyo). 23: 326. 1909.
帽蕊草属 mao rui cao shu
Herbs, parasitic on roots. Vegetative parts partly thalloid. Flowering shoot at first enclosed by a cupular volva, short, erect, unbranched. Inflorescence bracts scale-like, decussate in 4 ranks, concave, apicalmost largest and partly enclosing flower. Flowers bisexual, pale. Perianth cupular, truncate, persistent. Stamens very numerous, completely connate into a closed tube; connectives forming a depressed-conic cover over stigma, with a minute terminal opening, tube longitudinally dehiscent and entire structure caducous after flowering; anthers in a dense subterminal band, locules minute, connivent, extrorse, dehiscent by apical pores, initially covered by a thin irregularly ruptured membrane. Ovary superior; placentas 8-10(-15); integument 1. Style short and thick; stigma flat- to depressed-conic, obscurely 2-lobed.
Two species: one in Central America and one in tropical and subtropical Asia.
The distribution of this genus, with one species in Asia and the other in Central America, is unusual. Some authors place it within a separate family, Mitrastemonaceae, because of the bisexual flowers, but there are striking similarities in the floral structure such that there can be little doubt as to the close relationship to the rest of the Rafflesiaceae.
The generic name was spelled “Mitrastemma” in the protologue, but Makino later corrected the orthography to Mitrastemon (Bot. Mag. (Tokyo) 25: 253. 1911) and published the family name Mitrastemonaceae (loc. cit.: 252).