24- XVRIDACEAE — 25. ERIOCAULACEAE — 20. RAPATEACEAE 121 



FAMILY 24. XYRIDACEAE 



Herbs. Leaves radical, linear. Flowers in spikes or heads with an involucre 

 of imbricate bracts, hermaphrodite. Sepals 3, one much larger than the others 

 and deciduous. Petals 3, united below into a tube. Fertile stamens 3, adnate 

 to the petals ; staminodes 3. Anthers opening by longitudinal slits. Ov^ary 

 superior, i-celled or incompletely 3-celled. Ovules numerous, straight. Style 

 3-cleft. Fruit capsular. Embr^'o at the apex of the mealy albumen. (Plate 



Genus i, species 40. Tropical and South Africa. Some are used in medicine. 



Xyris L. 



FAMILY 25. ERIOCAULACEAE 



Herbs. Leaves radical, linear. Flowers in heads surrounded by an involu- 

 cre, verv small, monoecious. Perianth membranous, simple or double, rarely 

 in the female flowers none. Stamens 2 — 6. Anthers 2-celled. Ovary superior, 

 2 — 3-celled, with one pendulous ovule in each cell. Styles or style-branches 

 2 — 3. Fruit capsular. Embryo small, at the apex of the albumen. — Genera 4, 

 species 80. Tropical and South Africa. (Plate 15.) 



1. Stamens 2 — 3, opposite the petals. Petals of the male flowers united 



below, without a gland on the inside. Style-branches 6, three of which 

 bear a stigma, rarely 3. [Subfamily PAEPALANTHOIDEAE.] 2 



Stamens 4 — 6, very rarely fewer, but then petals free. Petals usually with 

 a gland on the inside near the apex. Style-branches 2 — 3, without 

 alternating appendages. [Subfamily ERIOCAULOIDEAE.] . . 3 



2. Petals of the female flowers united at their middle part. — Species 6. Central 



and South Africa. (Under Paepalanthits Mart.) Syngonanthus Ruhl. 



Petals of the female flowers free. — Species 3. West Africa and Mascarene 



Islands Paepalanthus Mart. 



3. Petals united into a tube, but free at the base in the female flowers. Inner 



involucral bracts more or less spreading. Stamens 6. — Species 8. 



Tropics. Some are used in medicine. (Plate 15.) Mesanthemum Koem. 



Petals free or absent. Inner involucral bracts rarely spreading. — Species 



60. Tropical and South Africa Eriocaulon L. 



SUBORDER BROMELIINEAE 

 FAMILY 26. RAPATEACEAE 



Herbs. Leaves radical, lanceolate. Flowers in heads with 2 large involucral 

 bracts, regular, hermaphrodite. Perianth corolla-like, yellow or whitish, 6- 

 lobed. Stamens 6, inserted in the tube of the perianth. Anthers linear, 

 opening by two terminal pores. Ovary superior, 3-celled, with i ascending, 

 inverted ovule in each cell. Style simple. Fruit capsular. Embryo near the 

 apex of the mealy albumen. 



Genus I, species i. West Africa (Liberia). Maschalocephalus Gilg & Schum. 



