Mitrastemonaceae Makino |

Mitrastema matudae
Mitrastema yamamotoi
A number of names of Mitrastema have been (and are currently being) used to refer to Asian material: M. cochinchinensis, M. sumatranus, M. kanehirai, M. kawasakii, and M. yamamotoi. The latter three names, originally proposed by Yamamoto (1925, 1926), were later used by Watanabe in a large number of publications in the 1930s (see references). Characters used to support the specific status of these taxa involved the number of scale leaves (up to six pairs vs. 8-12 pairs), their shape (small, elongate elliptic vs. large, oblong), and plant aspect (cylindrical vs. 4-angled, obconic). The most recent work to examine the taxonomy of Mitrastema was Meijer and Veldkamp (1993) who concluded that because many intermediates among these "species" exist, the variation represents local forms and ecotypes and that all Asian specimens should be regarded as one variable species. Moreover, as pointed out by van Royen (1963), all forms can be found in material from Papua New Guinea. Hansen (1973) stated that it was not possible to distinguish at the specific level the southeast Asian and Malesian populations. Although technically challenging given the rarity of these plants, a populational biosystematic study using molecular markers is likely required to determine whether one or more species exist in Asia. Until then, the conservative approach taken by Hansen (1973) and Meijer and Veldkamp (1993) will be followed here.
And finally, some words on the spelling of the generic and family names. The Latin "mitra" refers to mitre and "stema" to thread or stamen, aluding to the mitre-shaped staminal tube. Unfortunately, Makino (1909) accidentally used "stemma" which means garland or wreath, but being an orthographic error, it can be corrected under the rules of botanical nomenclature. There are several orthographic variants of the generic name, including Mitrastemma, Mitrastemon, and Mitrastema (I have not seen Mitrastemmon, but it's likely out there too!). These variants also spill over into the family name: Mitrastemonaceae Makino (in Bot. Mag. Tokyo 25:252) was conserved in 1966 (ICBN App. IB) and Mitrastemataceae (used by Mabberley in his 2008 edition of the Plant Book).
A proposal to conserve the name Mitrastemon was recently published by Reveal (Taxon 2010, 59: 299-300). It remains to be seen how the Committee for Vascular Plants will rule on this proposal.