Aquatic and Wetland Plants of Northeastern North America, Volume II: A Revised and Enlarged Edition of Norman C. Fassett's A Manual of Aquatic Plants, Volume II: Angiosperms: Monocotyledons

Subclass Commelinidae: Xyridaceae / Yellow-eyed-grass Family

Subclass Commelinidae Xyridaceae / Yellow-eyed-grass Family 1. Xyris (Yellow-eyed-grass) Emersed perennials; leaves grass-like, basal, 2-ranked, blades linear, abruptly or gradually dilated toward base; inflorescence a compact , head-like spike; flowers bisexual, borne in axils of leathery or chaffy, overlapping bracts, often a single flower open at a time; petals yellow; fruit a capsule. REFERENCES: Kral, 1966b, 1983, 1988; Malme, 1937. 1. Tips of lateral sepals extending beyond tips of subtending bracts (fig. 403b). 2. Keel of lateral sepals lacerate (fig. 403c) .................................................... 1. X. smalliana 2. Keel oflateral sepals ciliate (fig. 403g), fringed (fig. 404c), or entire (fig. 40Sg). 3. Plants bulbous and hard at base (fig. 403e) .............................................. 2. X. caroliniana 3. Plants soft and flattened at base. not bulbous. 4. Scapes SO-ISO em long. scabrous; keels of lateral sepals fringed ............................... 3. X.fimbriata 4. Scapes 3-45 em long. smooth; keels of lateral sepals entire .................................... 4. X. montana 1. Tips of lateral sepals enclosed by subtending bracts. 5. Keels oflateral sepals ciliate to ciliolate (fig. 40Sc) or scabrous. 6. Plants bulbous and hard at base (fig. 40Sa); lateral sepals tufted at tip (fig. 40Sc) . . . . . . . . . . . . . . . . . . . . . . . .. 5. X. torta 6. Plants soft and flattened at base. not bulbous; lateral sepals not tufted at tip .......................... 6. X. ambigua 5. Keels of lateral sepals lacerate (fig. 407g), erose. or dentate. 7. Plant bases bulbous. lowest outer leaves scale-like (fig. 407a); scapes twisted. often flexuous; upper portion ofleafbase conspicuously twisted .............................................................. 7. X. platylepis 7. Plant bases not bulbous, lower leaves not scale-like; scapes usually not twisted or flexuous; upper portion of leaf base not conspicuously twisted. S. Upper scape 4-ribbed, nearly round in cross-section. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Sb. X. diJJormis var. curtissii S. Upper scape 2(3)-ribbed, somewhat flattened. 9. Mature fruiting spikes 15 mm long or longer; seed surface mealy. 0.S-1.0 mm long or longer .......... 9. X. laxiJolia 9. Mature fruiting spikes less than 15 mm long (rarely 15 mm); seed surface not mealy. 0.4-0.5 mm long. 10. Plant bases pinkish or purplish. sometimes greenish; leaves spreading ............. Sa. X. diJJormis var. diJJormis 10. Plant bases pale yellow-green to straw-colored; leaves ascending ...... . . . . . . . . . . . . . . . . . . .. 10. X. jupicai l. X. smalliana Nash Fig. 403 Acid bogs, swamps, ditches, and lakeshores. Coastal plain, s. Me. s. to Fla., w. to Miss.; C.Am. (X. congdonii Small) 2. X. caroliniana Walt. Fig. 403 Moist sands, peaty pine barrens, and bogs. Coastal plain, N.J. s. to Fla., w. to Ark., e. Tex., and Mex.; C.Am. and S.Am. This bulbous species is often confused with X. torta. Xyris caroliniana, a more southerly coastal species, has lateral sepals which are long-fringed toward the tip. whereas X. torta, a more northeastern , inland species, has a tuft of fringe at the tip. 85 3. X. fimbriata Ell. Fig. 404 Sand, peat, and muck of pineland pools, swamps. ditches, and pond margins. Coastal plain, N.J. s. to Fla.• w. to Miss. and La. This is the easiest of all Xyris species to identify because of the scabrous scapes and fuzzy appearance of the lateral sepals. 4. X. montana Ries Fig. 405 Acid and rarely alkaline areas along riverbanks, in wet sand and peat. Nfld. and N.S. w. to N.B. and n. Mich., s. locally to n. N.J. and ne. Pa. b c g Fig. 403. Xyris smalliana: a. habit (NHAES); b. flowering spike (NHAES); c. lateral sepal (NHAES); d. seed (Kral, 1966b). Xyris caroliniana: e. habit (G&W); f. flowering spike (G&W); g. lateral sepal (Kral, 1966b); h. seed (Kral, 1966b). 86 b c lateral sepal bract Fig. 404. X,'" fimbria,"' ,. bah" (G&Wl' b. fto."ring ,pike (G&Wl; c. ,,""" "p,l (""l, J9666), d. "cd (K,"I, " stigmas pistil b remains of filaments (sometimes present) c style anther} stamen filament stigmas ------' scale - - d bristle Structure ofCyperaceae (sedges): a. section of stem with leaf base, generalized; b. flower, generalized; c. achene, generalized; d. spike/spikelet, generalized (F). 122 13. Lower leaf sheaths glabrous; perigynia somewhat inflated, obovoid with abrupt beak. 13. Lowerleaf sheathsscabroustohispidulous;perigyniaflattened,elliptic,taperingtominutebeak. 124 ANGIOSPERMS 17. Stems not arising from last year's leaves, bearing bladeless sheaths at base; leaf bases distinctly fringed. 21. Ligules rounded, about as long as wide or (fig. 43ge); pistillate spikes 2-10(15) em long .... " 15. C. emoryi 21. Ligules acute, longer than wide (fig. 4390); pistillate spikes 2-6(11) em long. 22...