Malaxis Soland. ex Sw.,
Prodr. Veg. Ind. Occ. (1778) 119
Sympodial terrestrialor sometimes epiphytic plants with very short to very long rhizomes. Stem few to many-leaved. Pseudobulbs present or not, consisting of one to several internodes, or, when absent, stem short to much elongated (then often creeping). Leaves sheathing at the base, glabrous, plicate (or not plicate in regions outside New Guinea), persistent, duplicate, green, light brown, or purple, sometimes with paler longitudinal bands or darker spots, thin-textured. Inflorescence terminal, a many-flowered (very rarely few-flowered) raceme. Flowers small to very small, not resupinate, often greenish or dark purple. Sepals free. Petals free, usually much narrower than the sepals. Lip without spur, not mobile, at the base usually with 2 lobes (auricles) that clasp the column. Column usually very short, sometimes elongated and then often provided with a horn-like dorsal projection. Column-foot absent. Pollinia 4, solid, caudicles absent, stipe absent, viscidium absent.
Cosmopolitan (but absent from New Zealand). About 300 species; in New Guinea c. 100 species, which upon revision will probably turn out to represent far less 'good' species.
Mainly terrestrial in lowland and montane forest, occasionally epiphytic on mossy tree trunks.
Members of this genus are small, soft-leaved plants, usually growing in moist shady spots on the forest floor, with plicate leaves and slender racemes with usually quite inconspicuous greenish or purplish flowers. The flowers are not resupinate. Malaxis is not common in cultivation, but several species would be well worth growing for their nicely coloured foliage, which may be e.g. bluish green with light brown bands, ochrish brown, or glossy purple. Most species have plain green leaves, however. In some species of section Pseudoliparis the column is almost indigo-blue.
Schlechter (1911-1914) has proposed an infrageneric classification for the New Guinea species of Malaxis (or rather Microstylis, as he called this genus). The comments we made under Liparis apply here as well, in that these section may not always conform to true clades, but that they are useful for identification purposes. Mainly for this reason we have retained Schlechter's classification, with some modifications.
We found it impossible to keep the sections Commelinodes and Crepidium (syn. Microstylis sect. Pleiodon Schltr.) separate. According to Schlechter, members of sect. Commelinodes should have elongated, decumbent and rooting stems, while sect. Crepidium should have short, crowded and erect stems that root only at the base. The flower structure, as Schlechter himself already noted, is identical in the two sections. But the vegetative differences are not at all as clear-cut as Schlechter implied. There are several species for which it would be quite arbitrary to assign them to one section or the other. For example, Malaxis vinicolor was included by Schlechter in section Crepidium (Pleiodon as Schlechter called it). As can be seen from the photograph of a type specimen ( 448-318T.JPG ) this species has quite elongated rhizomes, and except for the lower number of leaves there is no essential difference with a species like Malaxis fissa ( 448-83U.JPG ), which Schlechter included in section Commelinodes. Seidenfaden (1978) maintains the distinction between Commelinodes and Crepidium and suggests as an additional difference that the stems in sect. Commelinodes are not swollen, while in sect. Crepidium they are often swollen into pseudobulbs. Having seen living specimens of many species of Malaxis we have to disagree with the statement that the stem in sect. Commelinodes is never swollen. Summarising, we think that for the New Guinea members of the genus the distinction between sections Commelinodes and Crepidium can not be upheld. This was apparently also the position of J. J. Smith, since he included 'typical' species of sect. Commelinodes in sect. Crepidium. For the time being we retain sect. Herpetorhizis, which is characterised by the shoots appearing at long intervals along a creeping rhizome, but this should probably also be included in sect. Crepidium.
We agree with Smith (Smith, 1913) in uniting Schlechter's section Oistochilus with sect. Pseudoliparis. Finally, we consider that section Ophthalmodes is not well separable from sect. Holobos, since Malaxis carinatifolia (J.J.Sm.) P.F.Hunt could be accommodated in both. A key to the sections will be found below.
There have been various proposals to split up Malaxis into several smaller genera, notably by Szlachetko and his collaborators. In this view the New Guinea species of Malaxis should be distributed over the following genera: Crepidium, Dienia, Fingardia, Pseudoliparis and Saurolophorkis. However, these proposals are not backed by phylogenetic analyses and they are highly subjective, in our opinion, so we have decided not to follow them. Unfortunately, for several species of Crepidium, Dienia, Pseudoliparis and Saurolophorkis there is as yet no name available under Malaxis, and these species are found on this CD-ROM under the names of these 'unaccepted' genera.
Phylogenetic studies based on DNA sequence data have culminated in the recent treatment of Malaxis and related genera in Genera Orchidacearum vol. 4 (Pridgeon et al., 2005). According to this treatment the name Malaxis should be reserved for a group of species occurring in part of the neotropics as well as in continental Asia, Africa, Europe and North America. It would appear that these species all have not-plicate leaves. All the New Guinea species have plicate leaves and should be assigned to the genus Crepidium, with the exception of Malaxis ophrydis, which should be called Dienia ophrydis. We consider that more work is needed to fix the generic boundaries and to establish morphological support for the clades found in molecular studies.
Here, we still list all species under Malaxis, but the reader is of course free to turn to the synonyms list to check if there already is a name available under Crepidium and to use that instead.
Key to the New Guinea sections of Malaxis
1a. Lip in the apical part with denticulate margin or with 4 or more teeth or filaments ... 2
1b. Lip in the apical part entire or 2- or 3-lobulate ... 3
2a. Vegetative parts clearly differentiated into a long, creeping, leafless rhizome and short leafy shoots ... sect. Herpetorhizis
2b. Rhizome either very short or if elongated passing gradually into the leafy part of the stem ... sect. Crepidium (syn. sect. Pleiodon; sect. Commelinodes)
3a. Lip with basal lobes (auricles) more or less clasping the column ... 4
3a. Lip without basal auricles ... sect. Gastroglottis (genus Dienia)
4a. Lip entire or very indistinctly 3-lobed (not including the basal auricles), tip not bilobulate ... 5
4b. Lip distinctly 3-lobed (not including the basal auricles), often with a bilobulate tip ... sect. Hololobos (syn. sect. Ophthalmodes)
5a. Column often somewhat elongated, with large, often decurved apical wings or arms, often with a horn-like dorsal projection ... sect. Pseudoliparis (syn. sect. Oistochilus)
5b. Column very short, almost without a stalk, with indistinct apical wings, never with a dorsal projection ... sect. Bothrocardia
Species included on this CD-ROM:
Malaxis fasciata var. concolor
Malaxis nitida var. cyclopensis
Malaxis oligantha var. neuroglossa
Malaxis retusa var. brevis
Malaxis sciaphila var. bismarckiensis
Malaxis wariana var. oreogena