368 



MAVACACEAE. 



oblong, somewhat 4-sided, 2-celled. Ovary superior, sessile, i-celled with 3 

 parietal placentae; ovules several or numerous, orthotropous; style filiform; 

 stigmas terminal, entire or with 3 short lobes. Capsule i -celled, 3-valved. 

 Seeds ovoid or globose, the testa reticulated; embryo at the apex of the mealy 

 endosperm. 



The family consists of the following genus: 



i. MAYACA Aubl. PI. Guian. i: 42. 1775. 

 Characters of the family. [Aboriginal name of these plants in Guiana.] 



About 7 species are known, all natives of warm 

 and tropical America. Only the following occurs in 

 the United States. 



i. Mayaca Aubleti Michx. Mayaca. 

 (Fig. 892.) 



Mayaca Aubleti Michx. Fl. Bor. Am. i: 26. 1803. 

 Mayaca Michauxii Schott & Endl. Melet. i : 24. 1832. 



Stems tufted, s'-is' long, usually little 

 branched. Leaves densely clothing the stem and 

 widely speading, linear-lanceolate, translucent, 

 2 //_y/ long, about }" wide; peduncles ?."-{>" 

 long, very slender, recurved in fruit; flowers 3"- 

 4" broad, axillary, but borne near the ends of 

 branches, lateral, rarely more than one on each 

 branch; capsule oblong-oval, about as long as the 

 sepals, tipped until dehiscence by the subulate 

 style. 



In fresh water pools and streams, southeastern Vir- 

 ginia to Florida and Texas. May-July. 



Family 12. XYRIDACEAE Lindl. Nat. Syst. Ed. 2, 388. 1836. 



YELLOW-EYED GRASS FAMILY. 



Perennial or annual tufted herbs with basal narrow equitant commonly 

 2-ranked leaves, and erect simple leafless scapes. Flowers perfect, mostly yel- 

 low, nearly or quite regular, solitar}* and sessile in the axils of coriaceous imbri- 

 cated bracts (scales), forming terminal ovoid globose or cylindric heads. Sepals 

 3, the two lateral ones small, keeled, persistent, the other one larger, membran- 

 ous (wanting in the South American genus Abolboda). Corolla inferior, with 

 a narrow tube and 3 spreading lobes. Stamens 3, inserted on the corolla, usually 

 alternating with as many plumose or bearded staminodia. Ovary sessile, i -celled 

 or incompletely 3-celled; ovules numerous or few, on 3 parietal placentae, ortho- 

 tropous; style terminal (unappendaged in Xyris, in Abolboda appendaged at the 

 base), 3-branched above; stigmas apical. Fruit an oblong 3-valved capsule. 

 Seed-coat longitudinally striate. Embryo apical. Endosperm mealy or some- 

 what fleshy. 



Two genera, Xvris L. and Abolboda H. & B., comprising some 60 species, mostly of tropical 

 distribution in both the Old World and the New. 



i. XYRIS L,. Sp. PI. 42. 1753. 



Characters of the family as given above. [Greek name for some plant with 2-edged 

 leaves.] 



Besides the following species there are some 9 others in the southern United States. 

 Lateral sepals wingless, the keel fringed with short hairs. i. X.flexuosa. 



Lateral sepals winged, the keel fimbnate or lacerate. 



Scapes not bulbous-thickened at the base; leaves flat or but slightly twisted. 

 Lateral sepals about as long as the bracts, their keels lacerate. 



Head oblong, i l A"-s" long; northern. 2. X. montana. 



Head oval or ovoid, 3"-8 long; southern. 



Keel of lateral sepals lacerate to below the middle. 3. X. communis. 



Keel of lacerate sepals lacerate only above the middle. 4. X. Caroliniana. 



Lateral sepals longer than the bracts, their keels long-fimbriate. 5. X.fimbriata. 



Scapes conspicuously bulbous-thickened at the base; leaves spirally twisted. 6. X. tor/a. 



