Carex

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Carex

Description

Perennial herbs with tufted or creeping rhizome, monoecious, rarely dioecious. Leaves tristichous, usually narrowly linear, sheathing at the base, with a ligule at the junction of blade and sheath, rarely lanceolate or elliptic with a more or less distinct petiole and eligulate, mostly basal and subbasal, 0-several higher on the stem, the lower ones often reduced to bladeless sheaths; Inflorescence paniculiform, racemiform or spiciform, more rarely reduced to a single spikelet. Flowers unisexual, naked, solitary in the axils of the spirally arranged glumes;

Distribution

Asia-Tropical:, Jawa (Jawa present); New Guinea presentpresentpresentpresentpresentpresent; Philippines (Philippines present); Sulawesi (Sulawesi present) Australasia:, Tasmania (Tasmania present) E. Asia: present Luzon: present N. Sumatra: present New Caledonia: present New Zealand: present present SE. Asia: present Southern America:, Argentina Northeast (Formosa presentpresentpresent) northern hemisphere: present southern hemisphere: present present tropics of the Old World: present
A large genus with 600 to 1000 spp., the majority of them outside the tropics. However, the most primitive section, Vigneastra with a compound, paniculate inflorescence and androgynous spikelets, occurs mainly in the tropics of the Old World, from sea-level up to 3000 m. This section is represented in Malesia with 11 spp., and is there by far the largest section.
Subg. Carex is, besides with the 11 spp. of sect. Vigneastra, represented in Malesia by 25 sections and 49 spp., subg. Vignea with 6 sections and 6 spp.
Of the 66 spp. in all, 12 spp. are endemic and mostly confined to one island. Of the other 54 spp. the majority occur also in the northern hemisphere, either widely or only in SE. and/or E. Asia. Of these, 25 spp. extend without noticeable disjunctions into Malesia, either to its western part or further eastward. Another 4 of the E. Asian spp. occur in Formosa and in Malesia only in the Philippines (mostly only in Luzon), viz 12. C. satzumensis, 30. C. rhynchachaenium, 32. C. dolichostachya, and 33. C. formosensis.
Among the Asian spp. 4 show a distinct disjunction between SE. Asia and Java, viz 11. C. vesiculosa, 14. C. helferi, 63. C. nubigena, and 58. C. longipes (which is also once found in Celebes and once in New Guinea); all are mountain species.
A similar disjunction is found in the lowland species 10. C. stramentitia and 38. C. tricephala; this disjunction is understandable as both are bound to a distinct seasonal climate which shows a similar pattern (see van Steenis, Reinwardtia 5, 1961, 420-429).
Still larger disjunctions are shown by 5 E. Asian spp. which are in Malesia almost only found in New Guinea, Formosa being mostly the nearest station, viz 46. C. brachyathera, 47. C. finitima (also in N. Sumatra), 48. C. michauxiana, 56. C. bilateralis, and 61. C. duriuscula; all are mountain plants.
Not a few Carex spp. occur in both the northern and southern hemisphere (Australia, often Tasmania and New Zealand) and are also found in the intervening tropical zone in Malesia. There are 11 of such species in all. Among these the following 7 are found in more than one island, viz 6. C. indica, 31. C. breviculmis, 39. C. maculata, 40. C. capillacea, 57. C. brunnea, 5. C. hors- fieldii, and 64. C. echinata, although the latter two are very rare. Four others are also transtropical but are in Malesia only found in New Guinea, and thus show almost the same disjunction between Formosa and New Guinea as mentioned above; these are 43. C. brownii, 49. C. pseudocyperus, 55. C. gaudichaudiana, and 66. C. curta. They occur in Malesia only in bogs and marshes on (high) mountains.
The southern hemisphere has contributed very little to the Malesian Carices, as there is only one southern species from Australia, New Zealand, and New Caledonia, viz 62. C. appressa, which is found in Malesia, and then again only in New Guinea at very high altitude.
Summarizing, one cannot withdraw oneself from concluding that only the presence of mountain bogs, marshes and grasslands gives the opportunity for the maintenance of Carex in the Malesian tropics. This would explain why the big mountainous island of New Guinea — where this habitat is most abundantly represented, much more than in any other island — is so rich in species. It is then also understandable that this is the place where relict areas could maintain their last stand in the tropical mountains of Malesia.

Notes

The distinction of the sections is not always unanimously agreed on, and several species were put into different sections by different authors. Some sections are closely allied, the only difference being sometimes 2 versus 3 carpels. As this has great influence on the shape of the nut, it often is considered a very important character. In my opinion the difference is due to a minor genetic difference, and is taxonomically not very important. Besides, in some collections 2-carpelled and 3-carpelled fruits are found in the same inflorescence, e.g. in species of sect. Graciles, which has normally 2 carpels, and of sect. Oligostachyae (Decorae) which has normally 3 carpels (Noot.).

Citation

Endl., Gen. 1836: 110
Boeck. - in Linnaea. 1877: 145
Linne - in Philip. J. Sc. 1911: Bot. 57
B. & H. - in Gen. Pl. 1883: 1073
Ohwi - in Mem. Coll. Sc. Kyoto Imp. Un. 1936: 232
Boott - in Illustr. Genus Carex. 1858-1867
Pax - in E. & P., Nat. Pfl. Fam. 2. 1887: 122
Boeck. - in Linnaea. 1875: 14
Linne - in Philip. J. Sc. 1907: Bot. 107
Kuk. - in Pfl. R. Heft. 1909: 67
Linne - in Reinwardtia. 1954: 373
Raym. - in Mem. Jard. Bot. Montreal. 1959: 17
Kunth - in En. 1837: 368
Linne, Sp. Pl. 1753: 972
Clarke - in Fl. Br. Ind. 1894: 699
Steud. - in Syn. 1855: 182
Kern - in Back. & Bakh.f., Fl. Java 3. 1968: 487
Miq. - in Fl. Ind. Bat. 1856: 346
Linne - in J. Linn. Soc. Bot. 1904: 1
Linne - in Reinwardtia. 1951: 221
Koyama - in J. Fac. Sc. Un. Tokyo. 1962: 149
Nelmes, Kew Bull. 1946: 5
Boeck. - in Linnaea. 1876: 327