1. Wolffiella lingulata (Hegelm.) Hegelm. Fig. 296. 



Thalluses broadly oblong to linear, somewhat curved, 5-10 mm. long, 1-5 mm. 

 wide, the surfaces concave or channelled, the parent- and daughter-thalluses often 

 recurved and together appearing like a segment of a band. 



In freshwater pond in Tex. (Brazoria Co.); in La., Tex. and Calif., s. through 

 Latin Am. to Urug. 



2. WolffieUa gladiata (Hegelm.) Hegelm. Fig. 291. 



Thalluses 3.5-8 mm. long, 1-2 mm. wide at the broad base, tapered to an 

 obtuse-rounded apex, usually several or many cohering to form submerged colo- 

 nies, somewhat falcate. 



Growing in fresh nitrogenous water pond on Brazoria National Wildlife Refuge, 

 s.e. of Angleton. Brazoria Co., Tex., associated with Lemna, Riccia fliiitans and 

 Ricciacarpus natans {fide R. J. Fleetwood), spring-summer; La. and Tex., s. 

 through Latin Am. to Urug. 



3. Wolffiella floridana (J.D. Sm.) Thomps. Fig. 291. 



Thalluses fistulose, usually several in a group, sometimes paired or solitary, thin, 

 sickle-shaped or conically elongated, attenuate to an acuminate apex. 5-10 mm. 

 long, 0.4-0.7 mm. wide, green on all surfaces, often brown-punctate. 



On lakes and ponds in s.e. Okla. (McCurtain Co.) and e. Tex.; in inland waters 

 of the U.S. along the Atl. and Gulf coasts, and in the Miss. Valley n. to Mo. 



Fam. 29. Mayacaceae Kunth Bogmoss Family 



Small mosslike plants of wet soils and shallow flowing water; leaves cauline, 

 numerous, crowded on stem; peduncles axillary, 1 -flowered, arising along stem; 

 flowers perfect, regular, hypogynous, 3-merous; sepals and petals each 3, quite 

 distinct from each other; stamens 3, opposite the sepals; filaments filiform; anthers 

 oblong to ovoid, basifixed, opening by a terminal pore; ovary 1 -celled, superior; 

 ovules several; style filiform; fruit a 3-celled and 3-valved capsule, dehiscent 

 between the placentae. 



A monogeneric family. 



1. Mayaca Aubl. 



Characters of the family. About 10 species in tropical and warm-temperate 

 America, one in tropical Africa. 



1. Mayaca Aubletii Michx. Bogmoss. Fig. 297. 



Stems tufted or matted, to 2 dm. long, usually much less; leaves linear- 

 lanceolate, 3-5 mm. long, 1 -nerved; pedicels much-exceeding the leaves in length; 

 sepals lanceolate, about 4 mm. long; petals pink or whitish, obovate, about 4 mm. 

 long, persistent with sepals; capsule subglobose, about 4 mm. in diameter. M. 

 Michauxii Schott & Endl. 



Springy and seepage areas, mainly along and in streams, and about ponds in 

 s.e. Tex., May-July; on Coastal Plain from Va. (?) s. to Fla. and w. to Tex. 



A second species. M. fiuvioiilis Aubl.. with pedicels shorter than the leaves and 

 its capsule more ellipsoid, occurs east of Texas. It may eventually be discovered 

 in seepage areas in extreme southeast Texas. 



Fam. 30. Xyridaceae Agardh Yellow-eyed Grass Family 



Perennial or sometimes annual rushlike herbs with narrow mostly basal and 

 tufted leaves that sheath the lower part of a naked scape which is terminated by 



578 



