28 EKIOCAULACEAE. 



Order XYRIDALES. 



Terrestrial, commonly bog, herbs, or epiphytes in BROMELIACEAE. 

 Leaves often basal: blades prevailingly narrow. Inflorescence usually not 

 a spadix, but often with a spathe-like bract or a spathe. Flowers mostly 

 complete. Corolla regular or nearly so (except in some genera of COM- 

 MELINACEAE, PoNTEDERiACEAE and BROMELIACEAE). Gynoecium compound, 

 superior or rarely inferior. Fruit a capsule or utricle, or baccate. 



Ovary 1-celled, with parietal placentae : Inflorescence without a spathe. 



j Fam. 1. XYRIDACEAE. 

 Ovary 2-3-celled, if incompletely so or 11 nearly 1-celled 



then the flowers in a spathe. 

 Flowers minute, monoecious or dioecious, in dense 



heads each seated in an imbricated involucre. Fam. 2. EKIOCAULACEAE. 



Flowers conspicuous or relatively so, perfect. 



Terrestrial or aquatic plants : foliage not scurfy : 



stigmas united. 



Calyx and corolla free, of very different mem- 

 bers : stamens free. Fam. 3. COMMELIXACEAE. 

 Calyx and corolla of quite similar members and 

 partially united: stamens partially adnate 



to the perianth. Fam. 4. POXTEDERIACEAE. 



Epiphytes (our species), with scurfy foliage: 



stigmas 3. Fam. 5. BHOMELIACEAE. 



FAMILY 1. XYBJDACEAE. YELLOW-EYED GRASS FAMILY. 



Leaves basal : blades thickish. Flowers perfect, in a compact terminal 

 spike. Sepals 3, the two lateral ones firm, keeled and often appendaged, 

 persistent, the third larger, deciduous. Petals 3, fugacious: anthers 

 linear. Androecium of 3 stamens usually alternating with 3 staminodia. 

 Gynoecium 3-carpellary. Fruit a capsule. 



1. XYEIS [Gronov.] L. Eigid plants with basal equitant leaves and a 

 terminal spike with indurated bracts. 



1. X. arenicola Small. Leaves with dark dilated bases, 1-4 dm. long, usually 

 spirally twisted: scapes 3-7 dm. tall, somewhat flattened above, spirally 

 twisted: spikes cylindric or conic-oblong, 1.5-3 cm. long, often acute: lateral 

 sepals 8-12 mm. long; fringe of the wing firm: corolla yellow. Pinelands 

 and open sandy places, L. keys. [E. K.] YELLOW-EYED GRASS. 



FAMILY 2. EEIOCAULACEAE. PIPEWORT FAMILY. 



Perennial and perhaps rarely annual, mostly acaulescent, bog or 

 aquatic herbs. Leaves clustered : blades narrow. Scapes simple, subtended 

 by sheathing bracts. Flowers monoecious (androgynous), or rarely dioe- 

 cious, densely crowded in a terminal involucrate head. Perianth in 2 

 series (the inner rarely obsolete). Staminate flowers with as many stamens 

 as the sepals or twice as many. Pistillate flowers with a 2-3-celled ovary. 

 Fruit a capsule. 



1. LACHNOCAULON Kunth. Staminate flowers: sepals 3; petals obso- 

 lete; stamens 3; filaments united below, coalescent with a rudimentary corolla 

 or pistil, this with 3 lobes at the top; anthers 1-celled. Pistillate flowers: 

 sepals 3; petals obsolete. 



1. L. anceps (Walt.) Morong. Leaf -blades 2-6 cm. long, narrowly linear- 

 attenuate, sparingly pubescent or glabrate: scapes 0.5 dm. tall, very slender, 



