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  1. Family: Cyperaceae Juss.
    1. Genus: Rhynchospora Vahl
      1. Rhynchospora marliniana Naczi, W.M.Knapp & W.W.Thomas

        This species is accepted, and its native range is SE. Mexico to Honduras.


    Naczi, R.F.C., Knapp, W.M. & Thomas, W.W. Kew Bull (2012) 67: 771.

    Type: Belize, Toledo Distr., Naczi 11311 (holotype NY; isotypes BRH, DOV, K, MICH, MO, NY, US).
    Densely caespitose, erect, perennial herb
    Rhizomes 1 – 5 mm long, 0.8 – 2.2 mm wide; roots fibrous
    Culm bases surrounded by firm, chestnut or occasionally ochre, somewhat lustrous, old leaf sheaths; culms 17 – 59 cm tall, 0.3 – 0.8 mm wide at mid-height, suborbicular in cross-section, smooth, green
    Leaves 3 – 4 per culm, arising along proximal 13 – 33% of culm; sheaths 2.2 – 5.8 cm long, chestnut or ochre or pale yellow-brown on distal leaves; blades 5.1 – 13.3 cm long, 0.3 – 1 mm wide, the widest per plant 0.5 – 1 mm wide, green, the margins involute and minutely serrulate proximally, minutely serrulate distally, otherwise smooth
    Infructescences terminal, spiciform, congested, composed of bracteate fascicles spirally disposed on rachis, 0.9 – 3.1 cm long, 3 – 7.1% of culm height; bracts setaceous, 0.2 – 7.6 cm long, proximalmost exceeding infructescence; fascicles 4 – 7 per culm, 3.8 – 8.8 × 2.4 – 11 mm, imbricate or proximalmost ones separate, the internode between proximalmost fascicles 2.6 – 14 mm long; spikelets ovoid, 1 – 21 per fascicle, 2.5 – 3.4 × 1.2 – 1.3 mm, 1-flowered, on pedicels 0.2 – 0.6 mm long; scales spirally imbricate, 5 – 6 per spikelet, 0.7 – 2.4 × 0.8 – 3.2 mm, tightly surrounding achene, veinless except for midrib, obtuse or mucronulate, ferrugineous; distalmost scale of each spikelet the longest, 2 – 2.4 mm long, completely enwrapping the achene except for a small area of the proximal portion of the body
    Perianth bristles 6, 1.9 – 3.1 mm long, 1.1 – 1.5 times as long as achene [including tubercle (the persistent style base)], exceeding tubercle by 0.1 – 1 mm, medium or light brown; 3-zoned with proximal portion white-plumose, middle portion smooth, and distal portion minutely antrorsely denticulate; plumose portion 0.1 – 0.4 mm long, 4 – 20% length of bristle; smooth portion 0.3 – 1.1 mm long, 14 – 38% length of bristle; denticulate portion 1.5 – 2 mm long, 65 – 73% length of bristle; bristle tips gradually incurved over achene body
    Stamens 2 or occasionally 3, 1.5 – 1.7 mm long, anthers 0.3 – 0.4 mm long
    Achenes (including the tubercle) ovoid, 1.7 – 2.1 × 1 – 1.3 mm wide, 1.5 – 2 times as long as wide; bearing persistent perianth bristles; achene body 1.3 – 1.6 mm long, 1 – 1.5 times as long as wide, transversely rugulose over entire surface, suborbicular in cross-section, uniformly ferrugineous or occasionally light red-brown; tubercle compressed-deltoid, 0.3 – 0.6 mm long, 0.4 – 0.6 mm wide at base, 35 – 50% width of achene, 0.7 – 1.3 times as long as wide, fimbriate-denticulate, especially on margins and base
    Stigmas 2.
    Northern Central America in Belize (Belize, Cayo, Stann Creek, Toledo), northeastern Honduras (Gracias a Dios), southeastern Mexico (Tabasco), and northeastern Nicaragua (Atlántico Norte). Southeastern North America in southeastern USA (mid-panhandle Florida west to southeasternmost Mississippi).

    A naturally occurring, dry-season fire in Belize provided an opportunity to observe the response of Rhynchospora marliniana to burning. The fire occurred on 25 March 2008 at the type locality, and burned the ground and shrub layers in the savanna at this site (Fig. 3A). This savanna is subject to relatively frequent fires (the last one to have burned this particular site occurred about three years previously). When fires occur in this sparsely populated portion of Belize, usually humans do not extinguish them, and the fires burn themselves out. Such was the case with this fire. Field work on 13 April 2008, only 19 days after the fire, revealed vigorous vegetative growth in R. marliniana (Fig. 3B). In addition, the burned plants possessed culms with developing inflorescences (Fig. 3C). These inflorescences bore developing spikelets, none of which had yet flowered. The fire had burned the plants in their entirety except for their bases (Fig. 3D), composed mostly of sheaths of the basal leaves. Given their firm texture and apparently fire-resistant properties, these sheaths are likely adaptive for protecting the basal meristems from fire and enabling the rapid growth response after fires.

    Rhynchospora marliniana inhabits sites that are sunny, seasonally or permanently wet, nutrient-poor, and probably low-pH. Specifically, these sites are savannas (Fig. 2A), open pinelands (Fig. 2B), and, less commonly, edges of fast-moving and slow-moving blackwater streams (Figs 2C and D, respectively). Closely associated vascular plants include Arecaceae: Acoelorraphewrightii H. Wendl.; Burmanniaceae: Burmanniacapitata Mart.; Cyperaceae: Rhynchospora fascicularis (Michx.) Vahl, R. filifolia A. Gray, R. globosa (Kunth) Roem. & Schult., R. gracilenta A. Gray, R. oligantha A. Gray, R. plumosa, R. rugosa (Vahl) Gale, Scleriabracteata Cav., S. georgiana Core; Dilleniaceae: Curatellaamericana L.; Droseraceae: DroseracapillarisPoir.; Lentibulariaceae: Genliseafiliformis A. St.-Hil., UtriculariajunceaVahl; Lycopodiaceae: Lycopodiellacaroliniana (L.) Pic. Serm.; Pinaceae: Pinus caribaeaMorelet, P. palustris Mill.; Sarraceniaceae: Sarracenia flava L., S. leucophylla Raf., S. roseaNaczi, Case & R. B. Case. R. marliniana grows at elevations of 1 – 450 m. This species is quite local, but often common where it occurs.
    Near Threatened (NT) category of IUCN (2001). Rhynchospora marliniana does not appear to be threatened. Specimens document 10 populations collected since 2000. We discovered all but one of these in the course of this study, even though our work did not include a systematic survey for the species. Extensive populations in well-preserved habitat occur in at least three protected areas: Deep River Forest Reserve (Belize), Mountain Pine Ridge Forest Reserve (Belize), and Apalachicola National Forest (USA). Nevertheless, serious concerns exist about the future of R. marliniana. Even though R. marliniana occurs in both Central and North America, its range is relatively small (extent of occurrence c. 10,200 km2). Within this range, it is quite local, probably due in large part to its specialised habitat requirements (particularly limiting is the requirement for nutrient-poor soils). In addition, the range appears to be fragmented in all countries except Belize. Development is likely responsible for this fragmentation, and has been especially severe in the North American portion of the range. There, along the northern coast of the Gulf of Mexico, development has spread very rapidly within the past few decades, and continues to spread. Another threat, usually coincident with development, is fire suppression.

    We are pleased to name Rhynchospora marliniana in honour of the Marlin Family (Jacob, Kelly, Sofia, Shaman, and Hyla). The Marlins are leading advocates for the conservation of biological diversity in Belize. Their founding and continuing successful operation of the Belize Foundation for Research and Environmental Education (BFREE) are especially notable among their many achievements.

    Rhynchospora marliniana is unique in sect. Plumosae by having perianth bristles plumose only at their bases (Fig. 4A). The plumose portion of each bristle of R. marliniana is only 0.1 – 0.4 mm long, and comprises 4 – 20% of the total length of the bristle. All other members of sect. Plumosae have bristles plumed for 0.6 – 3.9 mm long, 40 – 91% of their total lengths (Fig. 4B). Rhynchospora marliniana is also unique by having a smooth zone on each bristle. This smooth zone is between the proximal, plumose zone and a distal, minutely denticulate zone. Thus, each bristle of R. marliniana is 3-zoned (Fig. 4A).

    All other members of sect. Plumosae have bristles that are covered with trichomes for their full lengths, a plumose zone proximally and a minutely denticulate zone distally (Fig. 4B). Thus, all members of sect. Plumosae have 2-zoned bristles, except R. marliniana.Rhynchospora marliniana most closely resembles R. plumosa. Accordingly, nearly all specimens collected prior to our work bore determinations of R. plumosa. Both species have relatively narrow leaf blades [widest leaf blade per specimen only 0.3 – 1 (– 1.8) mm wide], ovoid spikelets aggregated into fascicles (Fig. 5A), and relatively small achenes [achenes only 0.9 – 1.3 (– 1.4) mm wide]. Besides its unique features, R. marliniana is distinct from R. plumosa in two aspects. First, the plant bases of R. marliniana are dark brown and somewhat shiny, whereas those of R. plumosa are much paler (light or medium brown) and dull (Fig. 5B). Second, the perianth bristles of R. marliniana exceed the tubercle by 0.1 – 1 mm, whereas the bristles of R. plumosa usually are shorter than the tubercle (Fig. 4).

    Also relevant to the taxonomic status of Rhynchospora marliniana is its syntopy with R. plumosa. We observed syntopic occurrences of R. marliniana and R. plumosa at two sites: in Cayo District, Belize (R. marliniana: Naczi 11328, R. plumosa: Naczi 11327; R. marliniana: Naczi 12142, R. plumosa: Naczi 12143; all specimens from one, continuous habitat) and in Liberty County, Florida, USA (R. marliniana: Knapp 2546, R. plumosa: Knapp 2545; R. marliniana: Knapp 2558, R. plumosa: Knapp 2559; all specimens from one, continuous habitat). At each site, plants of R. marliniana grew within 10 m of R. plumosa plants, often closer. Indeed, plants of Naczi 12142 and Naczi 12143 grew completely intermingled, with plants of the two species separated by as little as 21 cm (distance from the centre of a plant of R. marliniana to the centre of the nearest plant of R. plumosa). However, we never observed plants that appeared to be hybrids or morphologic intermediates between R. marliniana and R. plumosa. In these instances of syntopy, plants of R. marliniana and R. plumosa naturally grew sufficiently close to interbreed, yet they retained their morphologic distinctions. Thus, syntopy strongly supports the status of R. marliniana as a species distinct from R. plumosa.

    Though similar to Rhynchospora plumosa of Rhynchospora sect. Plumosae, R. marliniana differs by its proximal leaf sheaths dark brown and shiny, perianth bristles plumose only at their bases, perianth bristles with a smooth zone between the plumose and minutely denticulate zones, and perianth bristles longer than the tubercle (the persistent style base).



    Native to:

    Belize, Honduras, Mexico Southeast

    Other Data

    Rhynchospora marliniana Naczi, W.M.Knapp & W.W.Thomas appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Jan 1, 2013 Naczi, R F.C. [11311], Belize K001096807 isotype


    First published in Kew Bull. 67: 771 (2012)

    Accepted by

    • Govaerts, R. (2019). World Checklist of Vascular Plants (WCVP Database) The Board of Trustees of the Royal Botanic Gardens, Kew.


    Kew Bulletin

    • Naczi, R. F. C. & Knapp, W. & Moore, G. (2010). Rhynchospora galeana, a new name for Rhynchospora breviseta (Gale) Channell (Cyperaceae). Brittonia 62: 96 – 97.CrossRefGoogle Scholar
    • Naczi, R. F. C. & Knapp, W. (2007). Circumscription of Rhynchospora section Plumosae (Cyperaceae), based on morphologic data. Botany 2007 meetings, American Society of Plant Taxonomists, Chicago, Illinois. Abstract: Accessed 5 July 2012.
    • Thomas, W. W. (1994). Rhynchospora , Cyperaceae. In: G. Davidse, M. Sousa S. & A. O. Chater (eds), Flora Mesoamericana, Vol. 6, Alismataceae a Cyperaceae, pp. 404 – 422. Inst. de Biología, Universidad Nacional Autónoma de México, México.Google Scholar
    • Thomas, W. W. (1992). A synopsis of Rhynchospora (Cyperaceae) in Mesoamerica. Brittonia 44: 14 – 44.CrossRefGoogle Scholar


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