Monographs Details: Rhynchospora holoschoenoides (Rich.) Herter
Authority: Maguire, Bassett. 1972. The botany of the Guayana Highland--part IX. Mem. New York Bot. Gard. 23: 1-832.
Family:Cyperaceae
Description:Distribution and Ecology - Distribution. Range showing the link between the American and the African tropics. In America widely spread from Central America and the West Indies through the Guayana and the Guianas southwards to Uruguay, but not occurring in Andean regions. In Africa rather frequent from Guinea eastwards to Mozambique and Natal, also in Madagascar and Mascarene Islands. The following specimens have been examined from the Guayana and its surrounding regions. TRINIDAD. O’Meara Savanna, Britton & Hazen 1568 (NY), Piarco, Dannouse 8254 (NY), Aripo Savanna, O. Kuntze 1041 (NY), Aripo Savanna, 20 m alt, Cowan & Richardson 1150 (NY, US). VENEZUELA. Falcon: Cerro Santa Ana, 800 m alt, Steyermark & Braun 94656 (NY, VEN); Monagas: Cerra de Garrancas, Ortiz 3 (MAR), morichal in savanna ca 7.5 km SW of Santa Barbara, 245 m alt, Pursell 8292 (NY); Guarico: between Hato San Mauricio and Santa Rita, Ramia & Trujillo 2682 (MAR); Guarico: Hato Píritu, 25 km to S of Calabozo, Tamayo s n (VEN); Bolívar: Alrededores de El Palmar, Trujillo 2315 (MAR), Chimatá Massif, vicinity of Techiné-Merú, along Río Aparurén, between mouth of Río Aparurén and Kon-quén, 470 m alt, Steyermark 76064 (F, NY), Altiplanicie de Nuria, E of Miamo, between Hato de Nuria and Cerro de Rancho Carata, 400 m alt, Steyermark 88791 (NY, VEN), between Río Caroní and Ciudad Bolívar, 200 m alt, Steyermark 57636 (F, NY), La Gran Sabana, about 2 km NW of Kamarata, 450 m alt, Koyama & Agostini 7262 (NY, VEN). GUYANA. Laina Savanna, Jenman 6137 (K, NY), SE of Georgetown, canal S of Lamaha Stopoff, East Coast Water Conservance, Hitchcock 16980 (NY, US), Northwest District, Wanama River, De La Cruz 3942 (NY), Turuk-wau, 3000 ft alt, Cook 132 (K, NY), Waranama Ranch, Berbice River, intermediate savanna, Harrison 982 (K, NY), Rupuruni, St. Ignatrin, Harrison 1306 (K, NY), Ituribisci Lake, Jenman 2257 (K, NY), Demerara, Jenman 6698 (K, NY), Upper Mazaruni River, Kukui River, Tillet & Tillet 45401 (NY), Southern Pakaraima Mts., Ireng River, between Waipa and Sand Hill Rapids, Maguire et al 46230 (NY), Ireng River, above Orindeick Falls, 2000 ft alt, Harrison 1396 (K, NY). SURINAME. Marataka River, Florschutz 1998 (NY, U), along Saramacca River, Km 40 from Paramaribo, coastal jungle road to Carl Francois, Maguire & Stahel 23600a (NY), Grote Zwiebelzwamp, road from Moengo Tapoe, Lanjouw & Lindeman 932 (NY, U). Zanderij I. Lanjouw 138 (NY, U), Lanjouw & Lindeman 232 (NY, U), Zanderij II, Maguire & Stahel 23648 & 25029 (NY), Zuid River, Kayser Airstrip, 45 km above confluence with Lucie River, 270 m alt, Irwin et al 57673 (NY). FRENCH GUIANA. Vicinity of Cayenne, Broadway 478, 575, 648 & 892 (NY).

Discussion:

[Schoenus cyperoides Swartz, Prodr. Veg. Ind. Occid. 19. 1788. Not of Retzius, 1786.J Schoenus holoschoenoides L. C. Richard, Act. Soc. Hist. Nat. Paris 1: 106. 1792. Type. French Guiana, Cayenne, Le Blond (P).

Scirpus muricatus Poiret, Encycl. Meth. Bot. 6: 765. 1805. Based on Lamarck’s plate.

[Schoenus polycephala [sic] Persoon, Syn. Pl. 1: 59. Apr.-Dec. 1805; in part. Superfluous name for Schoenus triceps Vahl and S. holoschoenoides L. C. Richard.]

Schoenus fragiferus Rudge, Pl. Guian. Icon. Descr. 15, t. 17. June, 1805. Type from British Guiana.

Rhynchospora cyperoides Martius, Denkschr. Akad. Wiss. München 6: 149. 1816-17. Based on Schoenus cyperoides Swartz, non Retzius.

[Rhynchospora globulifera Link, Jahrb. Gewächsk. 1(3): 76. 1820; in part. Superfluous name for Scirpus muricatus Poir. and Schoenus triceps Vahl.]

[Rhynchospora aurea Sieber ex Schultes, Mant. Pl. 2: 43. 1824. Not of Vahl.]

[Cephaloschoenus polycephalus (Persoon) Nees, Linnaea 9: 296. 1834. Based on Schoenus polycephalus Persoon, a superfluous name.]

[Ephippiorhynchium polycephalum (Persoon) Nees, Fl. Brasil. 2(1): 134, t. 12. 1842. Based on Schoenus polycephalus Persoon, a superfluous name.]

Ephippiorhynchium tenuirostre Nees, Fl. Brasil. 2(1): 135. 1842. Type. Brazil, Santa Catharina, Macrae, Sellow.

[Rhynchospora polycephala (Persoon) Wydler ex Kunth, Enum. PI. 2: 291. 1837. Based on Schoenus polycephalus Persoon, a superfluous name.]

Rhynchospora arechavaletae Böckeler, Cyper. Nov. 1: 24. 1888. Type. Uruguay, near Montevideo, Arechavaleta.

Rhynchospora spaerocephala Böckeler, Cyper. Nov. 1: 24. 1888. Type. Brazil, Glaziou 6434.

Rhynchospora riedeliana Gandoger, Bull. Soc. Bot. France 66: 298. 1920. Type. Brazil, Rio de Janeiro, Riedel 914.

Rhynchospora cyperoides Martius var triquetrifolia Kükenthal, Bot. Jahrb. 74: 435. 1949. Syntypes. Cuba, Ekman 11208 & 11378; Honduras, Schipp 790; Brazil, von Wied; and Mauritius, Urville in herb. Willdenow 1107 fol. 1.

Type. Le Blond (P) from French Guiana.

The traditional binomial, R. cyperoides, has to be replaced with R. holoschoenoides. The binomial, Schoenus cyperoides Swartz, on which R. cyperoides was based, is a later homonym of Retzius, and therefore is illegitimate. Hence, the name R. cyperoides dates only from 1816. The name, Schoenus holoschoenoides L. C. Richard, takes priority over all the synonyms pertaining to this taxon, and therefore the correct name of this species should be R. holoschoenoides (L. C. Richard) Herter.

Kükenthal in his monograph lists two varieties under this species, i e, var triceps and var triquetrijolia. The former variety sharply differs from R. holoschoenoides at least in the much larger achenes and spikelets, and can be kept as a distinct species. The latter variety was segregated by rather minor vegetative characters such as swollen triquetrous leaves and three-sided culms, a condition normally shown by the living specimens. Variety triquetrijolia thus becomes a mere synonym.

Rhynchospora arechavaletae is extremely similar to R. holoschoenoides. Böckeler, Kunth, Clarke, and Nelmes consider that these two are identical, while Böckeler, Osten, and Kükenthal regard R. arechavaletae to be specifically distinct from the latter in its rhizomatous habit and in the slightly larger (1.5 vs 2 mm long) achenes that are smooth in contrast to wrinkled ones in R. holoschoenoides. This distinction, however, is fictitious. Examination of the ample collections of the R. holoschoenoides complex shows that there is no correlation between the rhizomatous condition and the comparatively larger achenes. The achenes in the complex are normally only weakly rugulose and I failed to recognize any conspicuous difference between the rugulose and the smoothish surfaces of achenes. I treat R. arechavaletae as identical with R. holoschoenoides.

Distribution:Central America| West Indies| Guyana South America| French Guiana South America| Uruguay South America| Guinea Africa| Mozambique Africa| Madagascar Africa| Trinidad and Tobago South America| Venezuela South America| Suriname South America|