Rhynchospora nervosa subsp. ciliata (Vahl) T.Koyama
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Authority
Thomas, William W. 1984. The systematics of Rhynchospora section Dichromena. Mem. New York Bot. Gard. 37: 1-116.
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Family
Cyperaceae
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Scientific Name
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Description
Subspecies Description - Cespitose (Fig. 37d) perennial; culms erect to ascending, 9-75(-150) cm tall, 0.7-1.3 mm in diameter, green, glabrous to occasionally hirsute; leaves ca. 5-15 per culm, canaliculate to flat, green, ciliate along margins, glabrous to hirsute abaxially; basal leaves 8-50 cm long, 1.5-4.5 mm wide; cauline leaves 0-1 (-2) per culm; cauline blades 8-30 cm long, 1.7-4.3 mm wide; leaf sheaths 3-10 cm long, green, glabrous to hirsute, usually ciliate along inner band; summit of inner band concave, ciliate, hyaline; inflorescence bracts (Fig. 37c) (4-)5-7(-8), exceeding inflorescence, with basal portion usually parallel sided, ciliate basally along margins, usually hirsute abaxially but occasionally glabrous or almost so, occasionally sparsely pubescent adaxially; basal bract longest, 6-22 cm long, (1.4-)1.9-4(-5.2) mm wide at base of green portion, sometimes 1-2 mm below rest of inflorescence; white portion 1-3.5 cm long, smooth-textured, thicker than green portion; inflorescence a congested conical to hemispherical head of 5-16 spikelets; spikelets ovate to widely so, 5.1-9.3 mm long, 1.2-3.3 mm wide, consisting of 10-30 scales; scales white, often ferrugineously streaked, ovate, 3.5-5 mm long, 2.2-3.2 mm wide, cymbiform, carinate distally, occasionally ciliolate along keel; filaments 3.9-4.6 mm long; anthers 1.9-2.6 mm long; stigma and style 2.9-3.4 mm long; stigma branches 1.5-2.2 mm long; achenes (Fig. 10d) very widely obovate to widely depressed obovate, (0.95-) 1.05-1.5(-1.65) mm long, 1.1-1.4 (-1.6) mm wide, stramineous to dark brown; summit of achene slightly to strongly arched; shoulders of achene at edge of style base usually forming an angle but sometimes confluent; style base 0.2-0.85 mm high, 0.6-1.3 mm broad, shallowly to very shallowly triangular, brown to stramineous or grey; achene surface transversely rugulose; epidermal cells of achene narrowly elliptic, ± distinct. Flowering and Fruiting: Throughout its range, R. nervosa ssp. ciliata can be found flowering and fruiting at most times of the year; in Mexico and Central America, however, it blooms and sets seed predominantly in June, July and August. Distinguishing Features: This subspecies is characteristically cespitose, with bracts adaxially white. It is typically robust, with the leaves wide, often hirsute beneath and with the leaves equalling or exceeding the flowering culms. See Table VI and Fig. 36 for the differences between ssp. ciliata and ssp. nervosa.
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Discussion
Syntypes: America meridionali, Richard s.n. and Puerto Rico, West s.n. (C, syntypes, not seen; microfiche of syntypes at MICH). Schoenus ciliatus (Vahl) G. F. W. Meyer, Prim. FI. Esseq. 23. 1818. R. vahliana Grisebach, Fl. Br. West Ind. Isl. 577. 1864. R. ciliata Kükenthal, Bot. Jarhb. Syst. 56(Beibl. 125): 16. 1921. Rhynchospora nervosa var. ciliata (Vahl) Kükenthal, Bot. Jahrb. Syst. 75: 295. 1951, non Rhynchospora ciliaris [as 'ciliata’] (Michx.) Vahl, Enum. Pl. 2: 235. 1806 [Vahl’s incorrect publication of this name as R. ciliata should be viewed as an orthographic variant]. Dichromena ciliata Persoon, Syn. Pl. 1: 58. 1805. [as 'Dichroma']. Type: “Florida et insul. caribaeis. Kyll[inga]. triceps refert. Sw.” (L?, type not seen). Dichromena pura Nees in Martius, Fl. Bras. 2(1): 112. 1842. Type: St. Vincent, Lindley s.n. (CGE, holotype; NY, isotype). Rhynchospora pura (Nees) Grisebach, Fl. Br. West Ind. Isl. 577. 1864. Dichromena obtusifolia Schrader ex Nees in Martius, Fl. Bras. 2(1): 113. 1842. Type: Eastern Brazil, Sellow s.n. (G, lectotype, chosen here). Rhynchospora jelskiana Böckeler, Linnaea 38: 401. 1874. Type: French Guyana, Cayenne, 1867, K. de Jelski 987 (GH, lectotype, chosen here; GH, MO, US, photograph of destroyed holotype which was at B). Rhynchospora nervosa var. cinnamomea (Kükenthal) Kükenthal, Bot. Jahrb. Syst. 75: 297. 1951. Dichromena ciliata var. cinnamomea Kükenthal, Repert. Spec. Nov. Regni Veg. 23: 200. 1926. Type: Venezuela, Nueva Esparta, Isl. de Margarita, El Valle, 16 Jul 1901, Miller & Johnston 189 (NY, lectotype, chosen here; GH, MO, US, isolectotypes). Pollination: Several workers have observed bees visiting R. nervosa ssp. ciliata. Following is a list of insects collected while visiting this subspecies; the collectors are indicated (EL refers to Leppik (1955); DR refers to David Roubik, who was kind enough to share his data with me; WT refers to my own collections): WT Apis mellifera WT Augochloropsis (Augochloropsis) sp. WT Bombus ephippiatus WT B. mexicana WT, DR Megachile 2 spp. WT Pereirapis rhizophila WT, EL Trigona (Partamona) cupira DR, EL T. (Scaptotrigona) mexicana DR, EL T. (Scaptotrigona) pectoralis DR T. (Scaptotrigona) postica DR T. (Tetragono) clavipes DR T. (Tetragono) dorsalis luteiperennis EL T. (Trigona) fulviventris Because of the diversity of insect visitors that have been collected on this plant, and because pollen is carried on the bodies of visiting insects (Figs. 14d, e), I feel certain that this subspecies is insect-pollinated. Economic Uses: This plant has been cut and dried for use in mattresses in Dominica (Hodge 3214). Nomenclature: Koyama’s subspecies ciliata must be treated as new because he based it on Vahl’s illegitimate later homonym, D. ciliata, which was published one year later than Persoon's Dichroma ciliata (Dichroma is to be treated as an orthographic variant of Dichromena). Since Koyama cited Vahl’s publication, and since Vahl included a Latin description and cited types, the typification of this subspecies is essentially the same as that of Vahl s D. ciliata. The nomenclature of the two subspecies of R. nervosa changes drastically if these taxa are recognized at the varietal or specific levels in either Rhynchospora or Dichromena. This is due primarily to two different names (‘ciliata’ or 'nervosa’) being the earliest available ones for the species in either Rhynchospora or Dichromena. As two species in Rhynchospora the names for the two taxa would be R. nervosa (Vahl) Bockeler and R. ciliata Kük. As two species in Dichromena they would be Dichromena nervosa Vahl and D. ciliata Persoon (if this choice is made, then the type of Persoon’s name should be ascertained, if possible). As varieties in Rhynchospora, the names would be R. nervosa (Vahl) Bockeler var. nervosa and R. nervosa var. ciliata Kük. As varieties in Dichromena, the names would be D. ciliata Persoon var. ciliata and a new combination based on D. nervosa Vahl (according to the revision of the autonym rules at the International Botanical Congress in Sydney in 1981). As subspecies in Dichromena, a new name would have to be chosen for the subspecies corresponding to R. nervosa ssp. nervosa.
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Distribution
Habitat: This subspecies is characteristic of weedy areas such as pastures, roadsides, and lawns. Rhynchospora nervosa ssp. ciliata is seldom found in non-weedy settings. One such location, however, is the Mason River Field Station in Clarendon, Jamaica where Thomas 2126 was collected. This area is a boggy savanna with R. nervosa ssp. ciliata growing in the drier areas on a clay-loam with a pH of 5.
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