Xyris applanata

Description

Family Xyridaceae

Herbs perennial or rarely annual . Roots fibrous . Leaves mostly basal, distichous or sometimes polystichous , sheathing ; leaf blade ensiform , linear , or filiform . Scapes or peduncles usually numerous . Inflorescence terminal , a globose to cylindric head or dense spike; bracts conspicuous , spirally imbricate or decussate, persistent or sometimes caducous in fruit. Flowers bisexual , 3-merous. Sepals 3, sometimes median sepal reduced or absent, lateral sepals 2, chaffy-scarious, keeled . Corolla actinomorphic or rarely zygomorphic, usually ephemeral ; petals 3, yellow, less often white or blue, free , base clawed or sometimes connate , or forming a long tube . Stamens usually 3, inserted opposite petals; filaments short, adnate to petals, rarely free; anthers 2-loculed, dehiscing longitudinally. Staminodes present or absent. Ovary superior. Style filiform, apex 3-branched or simple . Capsule oblong , 3-valved, loculicidal. Seeds with copious and ± mealy endosperm; embryo small.

About five genera and ca. 300 species: widespread in tropical and subtropical regions; one genus and six species (one endemic) in China.Guofang Wu & Robert Kral "Xyridaceae". in Flora of China Vol. 24 Page 4. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org.

Genus Xyris

Herbs, perennial , occasionally annual , rosulate. Stems simple , erect , sometimes caudiciform, short to branching, elongate . Leaves alternate, 2-ranked, equitant; blade mostly linear to filiform , flattened to nearly terete , margins smooth to variously papillate or scabrous . Inflorescences: scapes variously elongate; spike bracts imbricate, the proximal sterile , decussate, distal ones fertile , in spiral [decussate], bearing medially, usually subapically, a distinct and mostly differently textured and colored "dorsal area" or this indistinct or absent. Flowers solitary in bract axils; sepals 3, distinct, unequal, lateral (outer) sepals distinct [connate ], chaffy , boat-shaped , chaffy, inner one membranous, capping corolla; keel papery , or scarious , variously winged , variously margined ; petals 3, distinct [to connate], equal, strongly clawed; blade ephemeral, spreading , yellow to white; staminodes 3, distinct, strongly clawed, apically yoked, bearded with moniliform hairs (rarely reduced, beardless) ; stamens 3, epipetalous ; anthers 2--4-locular; ovaries y thin-walled, placentation marginal to parietal [basal, free-central , axile ]; styles elongate, tubular , 3-branched; stigmas 3, U-shaped or funnelform . Capsules 3-valved, usually thin, loculicidal. Seeds [1--]15--90 or more, mealy or translucent , ovoid to cylindric , 0.3--1(--4) mm, variously lined and cross-lined; endosperm starchy and proteinaceous; embryo basal-lateral, minute. x = 9.

Species more than 250: North America, West Indies, Central America, South America, Asia, Africa, South Pacific Islands.

Most species of Xyris occur in the Guiana Highlands, Amazonia, and Brazilia in South America, with other smaller centers of endemism in Africa and Australasia."Xyris". in Flora of North America Vol. 22. Oxford University Press. Online at EFloras.org.

Taxonomy

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Domain: Eukaryota () - Whittaker & Margulis,1978
- Kingdom: Plantae () - Haeckel, 1866 - Plants
  - Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
    - Phylum: Tracheophyta () - Sinnott, 1935 Ex Cavalier-Smith, 1998 - Vascular Plants
      - Subphylum: Euphyllophytina ()
        Infraphylum: Radiatopses () - Kenrick & Crane, 1997
        Class: Liliopsida () - Scopoli, 1760
        Subclass: Commelinidae () - Takhtajan, 1967
        Superorder: Commelinanae () - Takhtajan, 1967
        Order: Xyridales () - Lindley, 1846
        Family: Xyridaceae () - C. Agardh, 1823 - Yellow-Eyed Grass Family
        Genus: Xyris () - Linnaeus, Sp. Pl. 1: 42. 1753; Gen. Pl. ed. 5; 25, 1754. - Yellow-eyed-grass [Greek xyron, razor, in reference to a plant with two-edged leaves]
        Specific epithet: applanata - Idrobo & L.B.Sm.
        Botanical name: - Xyris applanata Idrobo & L.B.Sm.

Notes

Publishing author : Idrobo & L.B.Sm. Publication : Caldasia 6: 238, fig. 27 1954

Similar Species

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Members of the genus Xyris

There are approximately 520 species in this genus. Here are just 100 of them:

X. aberdarica · X. acrophila · X. acuminata · X. acutifolia · X. adusta · X. aemula · X. affinis · X. alata · X. albescens · X. almae · X. altissima · X. ambigua (Coastalplain Yellow-Eyed Grass) · X. ambiqua · X. americana · X. amorimii · X. anceps · X. anceps var. minima · X. andina · X. angularis · X. angustifolia · X. anisophylla · X. applanata · X. apureana · X. aquatica · X. aracamunae · X. arachnoidea · X. araracuarae · X. araracuare · X. archeri · X. arescens · X. arisophylla · X. aristata · X. asperata · X. asperula · X. asterocephala · X. asterotricha · X. atrata · X. atriceps · X. atriceps marahuacae · X. atriceps neblinensis · X. atriceps subsp. chimantensis · X. atriceps subsp. marahuacae · X. atriceps subsp. neblinensis · X. atrovirida · X. augusto-coburgii · X. aurea · X. bahiana · X. bahiensis · X. bakeri · X. baldwiniana (Baldwin's Yelloweyed Grass) · X. bampsii · X. bancana · X. baronii · X. barteri · X. batokana · X. baumii · X. bialata · X. bicarinata · X. bicarnata · X. bicephala · X. bicostata · X. bicostata var. tillettii · X. bissei · X. blanchetiana · X. blepharophylla · X. bobartioides · X. boliviana · X. borneensis · X. boyacana · X. brachyfolia · X. brachysepala · X. bracteata · X. brasiliensis · X. brevifolia (Shortleaf Yelloweyed Grass) · X. brownei · X. brunnea · X. byssacea · X. cachimbensis · X. caerulea · X. calcarata · X. calcicola (Limestone Yellow-Eyed Grass) · X. calderoni · X. calderonii · X. calocephala · X. calostachys · X. capensis · X. capensis var. schoenoides · X. capillaris · X. capnoides · X. carinata · X. caroliniana (Carolina Yelloweyed Grass) · X. caroliniana f. phyllolepis · X. caulescens · X. celia · X. celiae · X. cheumatophila · X. chimantae · X. chinensis · X. chlorocephala · X. ciliata

Bibliography

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Wu Kuo-fang. 1997. Xyridaceae. In: Wu Kuo-fang, ed., Fl. Reipubl. Popularis Sin. 13(3): 11--19.
Kral, R. 1966b. The genus Xyris (Xyridaceae) in the southeastern United States and Canada. Sida 2: 177--260.
Kral, R. 1988. The genus Xyris (Xyridaceae) in Venezuela and contiguous northern South America. Ann. Missouri Bot. Gard. 75: 522--722.