Machaerina

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Machaerina

Description

Perennial herbs with horizontally creeping or short rhizome often emitting creeping stolons. Leaves distichously arranged, vertically much flattened, angled, or terete, smooth, sometimes asperous, rarely transversely septate; Inflorescence paniculate, consisting of few to several partial panicles; Stamens (1-2-)3, with free filaments and linear anthers;

Distribution

Africa: present America: present Asia-Tropical:, New Guinea present Australasia: Mt Kinabalu: present tropical Asia: present
About 45 spp., chiefly Australian, a few spp. in tropical Asia, Africa, and America, some spp. extending to the subtropics; in Malesia 12 spp., of which 3 endemic: M. aspericaulis (Mt Kinabalu), M. disticha (see map), and M. lamii (New Guinea).

Notes

In the first half of the 19th century Cladium, Machaerina, Vincentia, Baumea, and Chapelliera were generally treated as separate genera, e.g. by KUNTH, STEUDEL, and BOECKELER. Mainly on account of the supposedly spiral arrangement of the glumes in all these genera and the distribution of sexes in the spikelet (lowest flower fertile), BENTHAM united them under the name Cladium. He was followed by nearly all subsequent authors, such as CLARKE, and recently by KÜKENTHAL. However, only in Cladium sensu stricto the glumes are spirally arranged, and the distribution of sexes is less constant than assumed, especially in Cladium mariscus, in which often the lowest flower is male or functionally male. Already PALLA and STAPF were of the opinion that BENTHAM's circumscription was untenable, PALLA mainly for anatomical reasons, and recently KOYAMA divided Cladium sensu BENTHAM into two well characterized genera, which can be distinguished as follows:
CladiumMachaerina
Stems hollow.Stems pithy.
Partial inflorescences corymbiform.Partial inflorescences paniculiform.
Leaves 3-ranked.Leaves 2-ranked.
Leaf-blades horizontally flattened, serrate-scabrous on the margins.Leaf-blades vertically flattened to terete, smooth on the margins or nearly so.
Stamens 2(-3?).Stamens (1-)3.
Glumes spiral.Glumes distichous.
Nut supported by a disc.No disc under the nut.
Pollen of 1-6 aperture type (according to Miss M. IKUSE, in KOYAMA, l.c.).Pollen of polyforate type.

Machaerina is undoubtedly much nearer to Gahnia than to Cladium. It seems advisable to keep Gahnia as a separate genus, as it is rather sharply distinguishable from Machaerina by the always terete stems, the spirally arranged, horizontally flattened leaves scabrous on the margins and narrowed into a long subulate tail, the long lower bracts, the always 1-2-flowered spikelets (lower flower when present sterile or male), the small fertile glumes (smaller than the outer sterile ones), the number of stamens (3-6), and the very small style-base. The fact that in some Machaerinae fruit dispersal is similar to that found in Gahnia, also points to the close relationship between these two genera. Fixing mechanism is found in M. mariscoides, M. gunnii, and some extra-Malesian species. Fruit dispersal in M. sinclairii (strong postfloral growth of the filaments to which the nut remains attached) is similar to the braiding mechanism found in several Gahniae.
Specific delimitation presents great difficulties throughout the genus. Especially the delimitation of species 1-5 is rather vague. In M. glomerata, M. mariscoides, and M. rubiginosa several races are involved.

Citation

MIQ. - in Fl. Ind. Bat. 1856: 339
KOYAMA - in Bot. Mag. Tokyo. 1956: 61
KUNTH - in En. 1837: 315
PAX - in E.& P., Pfl.Fam. 2. 1887: 116
BOECK. - in Linnaea. 1874: 251
STAPF - in Gibbs, J. Linn. Soc. Bot. 42. 1914: 178
KUNTH - in En. 1837: 314
KUNTH - in En. 1837: 313
KUNTH - in En. 1837: 313
KERN - in Act. Bot. Néerl. 1959: 263
PAX - in E.& P., Pfl.Fam. 2. 1887: 116
BOECK. - in Linnaea. 1874: 247
MIQ. - in Fl. Ind. Bat. 1856: 339
BOECK. - in Linnaea. 1874: 237