Chloridoideae

Saltgrass Distichlis spicata, copyright Jim Morefield.

Belongs within: Poaceae.
Contains: Muhlenbergia, Zoysieae, Sporobolus, Chlorideae, Pappophoreae, Eragrostis, Triodia.

The Chloridoideae is a clade of mostly C4 grasses supported by molecular analysis but with no identified morphological synapomorphies as yet. However, the clade of chloridoids excluding ‘Merxmuellera’ rangei and Centropodia is supported by the presence of ‘chloridoid-type’ microhairs with short and wide apical cells (Grass Phylogeny Working Group 2001). Subgroups include the Eragrostideae, which bear unspecialised spikelets usually with several florets, three-veined lemmas, and a rather cartilaginous texture. Uniola, the sea oats, is a New World genus bearing strongly flattened and keeled spikelets on long pedicels (Voss 1972). Distichlis, the saltgrasses, are rhizomatous or stoloniferous grasses with conspicuously distichous leaves.

Characters (from Grass Phylogeny Working Group 2001): Plants annual or perennial (rhizomatous, stoloniferous, caespitose or decumbent), herbaceous (rarely woody), of dry climates, especially in the tropics and subtropics, also found in the temperate zone. Culms solid or hollow. Leaves distichous; abaxial ligule usually absent, rarely present as a line of hairs; adaxial ligule a fringed or less commonly unfringed membrane; blades relatively narrow, without pseudopetioles, venation parallel; sheaths usually non-auriculate. Inflorescences paniculate, paniculate with spicate branches, racemose, or spicate, bracts outside of the spikelets absent. Spikelets bisexual or sometimes unisexual (if so the plants dioecious or monoecious), with glumes 2, rarely a sterile lemma, and female-fertile florets 1 to many, apical reduction usually present, usually laterally compressed, sometimes dorsally compressed, usually disarticulating above the glumes (below in a few Eragrostis species); lemma lacking uncinate macrohairs, if awned, the awns single or if multiple, lacking a basal column; palea well developed; lodicules 2 or absent, fleshy, glabrous; stamens 1 to 3; ovary glabrous, apical appendage absent, haustorial synergids absent, styles 2, free, close, stigmas 2. Caryopsis with the pericarp often free or loose; hilum short; endosperm hard, without lipid, containing simple or compound starch grains; embryo large or rarely small, epiblast present or rarely absent, scutellar cleft present, mesocotyl internode elongated, embryonic leaf margins meeting or rarely overlapping. Foliar mesophyll usually radiate, without an adaxial palisade layer, fusoid cells absent, arm cells absent; Kranz anatomy present; midrib simple; adaxial bulliform cells present. Foliar stomata with dome-shaped or triangular subsidiary cells; bicellular microhairs present, usually chloridoid-type; papillae absent or present.

<==Chloridoideae [Eragrostoideae, Pappophoroideae]
    |--+--‘Merxmuellera’ rangeiGPWG01
    |  `--Centropodia glaucaGPWG01
    `--+--+--+--ZoysieaeS06
       |  |  `--+--SporobolusGPWG01
       |  |     `--ChlorideaeGPWG01
       |  `--DistichlisGPWG01
       |       |--D. scopariaCLB06
       |       `--D. spicata (Linnaeus) Greene 1887S06 (see below for synonymy)
       |            |  i. s.: D. s. f. hirta [=D. hirta Phil. 1873]S06
       |            |         D. s. var. mendozina [=D. thalassica var. mendozina]S06
       |            |         D. s. var. thalassicaS06 [=Megastachya thalassicaS06, Poa thalassicaB78, Uniola thalassicaS06]
       |            |--D. s. ssp. spicataGPWG01
       |            `--D. s. ssp. strictaGPWG01
       `--+--PappophoreaeGPWG01
          `--+--UniolaGPWG01
             |    |--U. latifoliaV72
             |    `--U. paniculataGPWG01
             `--EragrostideaeGPWG01
                  |--EragrostisGPWG01
                  |--TriodiaM99
                  `--DactylocteniumM99
                       |--D. aegyptium (Lin.) Richter 1890S06 (see below for synonymy)
                       |--D. mucronatumC55
                       |--D. radulans (Br.) Beauv. 1812G52 [=Eleusine radulansB78; incl. D. australienseG52]
                       `--D. scindicumPP07
Chloridoideae incertae sedis:
  TridensGPWG01
    |--T. albescensHW96
    |--T. flavusGPWG01 [=Triodia flavaV72]
    `--T. muticusH93
  MuhlenbergiaGPWG01
  Cynodon [Cynodonteae]GPWG01
    |--C. ciliarisB78
    |--C. dactylon (Linnaeus) Persoon 1805PL04 [=Panicum dactylonB78]
    |    |--C. d. var. dactylonB78
    |    `--C. d. var. pulchellusB78
    |--C. nlemfuensisLK14
    |--C. plectostachyusH93
    `--C. transvaalensisH93
  Lepturus [Leptureae]GPWG01
    `--L. repensC78
  Orcuttia [Orcuttieae]GPWG01
    |--O. californicaH93
    |--O. inaequalis [=O. californica var. inaequalis]H93
    |--O. pilosaH93
    |--O. tenuisH93
    `--O. viscida [=O. californica var. viscida]H93

Dactyloctenium aegyptium (Lin.) Richter 1890S06 [=Cynosurus aegyptius Lin. 1753S06, Eleusine aegyptia (Lin.) Pers. 1805S06; incl. Dactyloctenium aegyptiacum Willd. 1809S06, E. cruciataB78]

Distichlis spicata (Linnaeus) Greene 1887S06 [=Uniola spicata Linnaeus 1853S06, Brizopyrum spicatumS06; incl. Poa distichophyllaB78, Festuca distichophyllaB78, Uniola distichophyllaS06, Distichlis spicata var. divaricataH93, D. maritima Rafin. 1819S06, Poa michauxiiS06, D. spicata var. nanaH93, P. paradoxaB78, D. spicata var. stoloniferaH93]

*Type species of generic name indicated

References

[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[C78] Clunie, N. M. U. 1978. The vegetation. In: Womersley, J. S. (ed.) Handbooks of the Flora of Papua New Guinea vol. 1 pp. 1–11. Melbourne University Press: Carlton South (Australia).

[CLB06] Cutrera, A. P., E. A. Lacey & C. Busch. 2006. Intraspecific variation in effective population size in talar tuco-tucos (Ctenomys talarum): the role of demography. Journal of Mammalogy 87 (1): 108–116.

[G52] Gardner, C. A. 1952. Flora of Western Australia vol. 1 pt 1. Gramineae. William H. Wyatt: Perth.

[GPWG01] Grass Phylogeny Working Group. 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Annals of the Missouri Botanical Garden 88 (3): 373–457.

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[HW96] Hicks, A. L., & R. F. Whitcomb. 1996. Diversity of the leafhopper (Homoptera: Cicadellidae) fauna of northern Chihuahuan grasslands, with emphasis on gypsum grasslands and description of a new species of Athysanella (Cicadellidae: Deltocephalinae). Proceedings of the Entomological Society of Washington 98 (1): 145–157.

[LK14] Lyons, M. N., G. J. Keighery, L. A. Gibson & T. Handasyde. 2014. Flora and vegetation communities of selected islands off the Kimberley coast of Western Australia. Records of the Western Australian Museum Supplement 81: 205–244.

[M99] Matthews, M. 1999. Heliothine Moths of Australia: A guide to bollworms and related noctuid groups. CSIRO Publishing.

[PP07] Pandey, R. P., & P. M. Padhye. 2007. Studies on phytodiversity of Arid Machia Safari Park-Kailana in Jodhpur (Rajasthan). Bulletin of the Botanical Survey of India 4: 15–78.

[PL04] Pohl, G., & I. Lenski. 2004. Zur Verbreitung und Vergesellschaftung von Pennisetum orientale Rich. in Nordeuböa (Griechenland) (Poaceae, Paniceae). Senckenbergiana Biologica 83 (2): 209–223.

[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 409–555.

[V72] Voss, E. G. 1972. Michigan Flora. Part I. Gymnosperms and Monocots. Cranbrook Institute of Science and University of Michigan Herbarium.

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