Cyperus bampsii Verloove & G.C. Tucker, 2017

Verloove, Filip & Tucker, Gordon, 2017, A new species of Cyperus (Cyperaceae) from Brazil, Phytotaxa 323 (3), pp. 275-281 : 276-278

Cyperus bampsii Verloove & G.C. Tucker , spec. nov. ( Fig. 1 and 2 )

Type — Brazil, Santa Cruz, 14 km W de Belterra W 55°00’ S 2°40’, Rio Tapajoz , Est. Pará, 40 m, forêt rivulaire, sur sable mouilleux [riparian woodland, on damp sand] ; herbe cespiteuse de 10 cm de haut, épillets blanchâtres [cespitose herb 10 cm tall, spikelets whitish], 30 January 1976, Bamps P. 5283 (holotype BR; isotypes RB, US) .

Herbs, annual, cespitose, with reddish roots. Culms trigonous, 12–18 cm × 1–1.5 mm, soft (flattened in drying), glabrous. Leaves usually reduced to sheaths, these densely red-speckled, occasionally with blades, V-shaped to semiterete, 12 cm × 2 mm, C 3 photosynthetic type. Inflorescences: heads loosely digitate; rays 4–12, very unequal, 0–40 mm; 2d order rays sometimes present, up to 10 mm; bracts 2, horizontal to ascending, much shorter than the rays, 4–8 mm, occasionally longer. Spikelets 1–4(–6), linear, ± compressed, 7–21 × 1.5–2 mm; glumes 14–42, laterally whitish green, dull, medially green, laterally 1-ribbed, medially 1(–2)-ribbed, oblong to obovate, c. 1.6 × 1 mm, apex with blunt, straight mucro 0.2 mm, glabrous. Flowers: stamens 3; anthers 0.4–0.5 mm; styles c. 0.6 mm; stigmas 3, 0.6–0.8 mm. Achenes bluntly trigonous, c. ⅓ as long as floral scale, whitish turning orange-brown at maturity, shortly stipitate, globose, c. 0.7 × 0.6 mm, apex obtuse, surfaces nearly smooth, striate, with rectangular cells.

Recognition. Similar to Cyperus haspan but differs in being a cespitose annual (vs. a usually rhizomatous perennial), its longer spikelets and shorter involucral bracts, its greenish white glumes that are obtuse at apex (vs. glumes reddish and acute at apex), its anthers that are not appendaged (vs. anther connective usually bearing a stellate tuft of trichomes), and its darker, slightly larger achenes with smooth surfaces (vs. achene surface granular to papillosetuberculate).

Distribution. South America: Brazil, Pará, only known so far from the type locality. Several relevant virtual herbaria were verified (see ‘Materials and methods’) but no additional collections could be traced so far.

Habitat. On damp sand in riparian woodland. 10– 100 m. In the same area the following species (mostly shrubs and trees) were recorded by the collector (comm. P. Bamps, July 2016): Acalypha spec. , Byrsonima chrysophylla Kunth , Campsiandra laurifolia Benth. , Mollia lepidota Spruce ex Benth. , Swartzia spec. , Tabebuia barbata (E. Mey.) Sandwith , Tabernaemontana siphilitica ( L. f.) Leeuwenb. and Warszewiczia coccinea (Vahl) Klotzsch.

Conservation status. It is problematic to assign an IUCN conservation status to species only known from the type collection; however, its limited occurrence would fit the category of Critically Endangered ( CR), according to IUCN Red List criteria ( IUCN, 2001). Of the ca. 230 species of Cyperus in the Neotropics, 16 are known from 3 or fewer collections, and 10, including C. bampsii , are known from only the type collection.

Etymology. Cyperus bampsii is named in honor of its discoverer, Paul Joseph Rodolphe Bamps (1932–), a Belgian botanist with special interest for agronomy in tropical regions, especially in Central Africa, and former curator of the herbarium of the Botanic Garden of Meise, Belgium. Bamps also made collecting trips to South America, including visits to Brazil.

Notes (see also illustrations and Table 1). Based on Kükenthal (1935 –1936), Cyperus bampsii evidently belongs to what was then known as subgenus Eucyperus (rachilla non-articulate, style trifid), pars Pycnostachys (spikelets digitately arranged). This large group is now treated as Cyperus subgenus Anosporum (Nees) C. B. Clarke ( Larridon & al., 2011). The anthelate (not congested) inflorescences, relatively slender, almost leafless culms and small glumes and achenes exclude all sections of subgenus Pycnostachys , except section Fusci (Kunth) C.B. Clarke , section Haspani (Kunth) C.B. Clarke and section Amabiles C.B. Clarke. Section Fusci accommodates slender annuals with leafy stems, achenes that are at least ½ as long as the glumes and flowers with a single stamen, while C. bampsii has (almost) leafless culms, achenes that are less than half as long as the glume and three stamens per flower. Species from section Amabiles usually have glumes that are thicker in texture, often with a more pronounced mucro, and achenes tend to be oblong rather than obovate. Its type, C. amabilis , is much reminiscent of C. bampsii in general appearance, both being tufted, multi-stemmed annuals. However, C. amabilis has reddish-maroon glumes with a short, straight to slightly excurved arista and its androecium is 1-staminate. Moreover, C. amabilis is a known C 4 -plant (e.g. Bruhl & Wilson 2007). C. bampsii obviously fits best in section Haspani and, in fact, bears some resemblance to C. haspan and the closely related C. foliaceus C.B. Clarke and C. tenuispica Steudel , all annuals or slender perennials with short, slender rhizomes. On morphological grounds, these may be the closest relatives of C. bampsii . All these species are also C 3 -plants ( Bruhl & Wilson 2007; authors’ observations), although photosynthetic pathway is only informative phylogenetically at the subgeneric rank.

Out of these species C. bampsii is perhaps most reminiscent of C. tenuispica in general appearance, the latter being a species from the Old World tropics (Africa, Asia and Australia) but locally naturalized in Central and South America. Both are cespitose annuals with several stems, spikelets in digitate clusters and they roughly correspond in floral characters as well. However, in C. tenuispica (like in C. foliaceus , also from tropical Africa) involucral bracts are more numerous and much longer, some at least greatly exceeding the rays ( Beentje 2010). Also, in these Old World species glumes tend to be more laxly arranged (with the rachilla showing through) and achenes are distinctly sculptured (papillose to tuberculate, with raised cell-walls) and usually a trifle smaller. The pantropical and exceedingly variable C. haspan is also similar. However, the latter is a perennial with short but distinct, often creeping rhizomes. Like in C. bampsii it has involucral bracts that are usually shorter than the rays but they are always well-developed and leaf-like, the longest up to 12 or even 18 cm long (e.g. Tucker & al. 2002, Beentje 2010). In C. bampsii , on the contrary, the bracts are very short, not leaf-like and rarely exceed 10 mm in length. Spikelet length and, as a consequence, number of glumes are variable in C. haspan . However, as a rule, spikelets are relatively short (up to 10 or 12 mm; e.g. Kükenthal 1935 –1936, Beentje 2010), while they are much longer (up to 21 mm) and more-flowered (up to 42 glumes per spikelet) in C. bampsii . Both species also differ in glume color, those of C. bampsii being much paler (usually light to dark brown or reddish-brown to almost black in C. haspan ; Beentje 2010). A feature often encountered in C. haspan are anthers that are white setose at apex (e.g. Kükenthal 1935 –1936, Kern 1974, Tucker 1994, Dai & al. 2010), a feature not found in C. bampsii . Finally, both species also markedly differ in achene characters: while these are always densely granulate to verruculose in C. haspan , they are nearly smooth (at most inconspicuously striate with rectangular cells) in C. bampsii (see Figure 2 ). Moreover, the achenes tend to be darker and slightly larger in the latter as well. The value of achene surface features in Cyperaceae has been confirmed on numerous occasions (e.g. Denton 1983, Tucker & Miller 1989, Shalabi & Gazer 2015, Patil & Prasad 2016). Hefler & Longhi-Wagner (2008) found that in Cyperus most important fruit characters were surface ornamentation, distribution and shape of the epidermal cells, height and limits of the anticlinal walls, type of silica bodies and presence or absence of connections between these and the anticlinal walls. In this respect, C. bampsii clearly differs from its putative relatives.

Figures

FIGURE 1. Cyperus bampsii. A = habit, B = leaf, C = inflorescence, D = spike, E = spikelet, F = glume, G = achene with stigma and stamens (drawn after P.Bamps 5283, BR).

FIGURE 2. SEM photos (100 and 10 ųm) of achenes of C. bampsii, C. haspan and C. amabilis. (Based on P.Bamps 5283, C.G. Pringle 3283 in Plantae Mexicanae 1890 and C.G. Pringle 811 in Plantae Mexicanae 1886 respectively, all from BR).