THE MONOCOTYLEDOXES 



1979 



V 



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Fig. iQog. — Tradescantia virginica. Flower 

 with leafy bracts. 



The Eriocaulaceae are small, 

 perennial herbs with shortened axes 

 and dense tufts of narrow, grasslike, 

 radical leaves from which arise one 

 or more simple, slender scapes bear- 

 ing more or less spherical capitula 

 of flowers. The individual flowers 

 are minute and unisexual by abortion 

 and the inflorescence is surrounded 

 by an involucre. The perianth is 

 hyaline or membranous, usually 

 sepaloid, and composed of two 

 whorls. Male flowers have four to six 

 stamens; female flowers possess an 

 ovary composed of two or three car- 

 pels with oneorthotropous, pendulous 

 ovule in each loculus. The fruit is a capsule and the seed is endospermic. 



The family contains about 600 species grouped in some nine genera, of 

 which Eriocaulon, with some 250 species, is the best known. E. septongulare 

 (Fig. 19 10) is found in the north-west of Scotland and in west Ireland, 

 though it is really a North American species. The other genera, of which 

 Paepalanthiis, with 215 species, is the largest, are restricted mainly to 

 tropical South America. 



Fig. 19 10. — Eriocaulon septaugiilare. The 

 inflorescence stalks bear small capitula 

 of flowers surrounded by an invo- 

 lucre of bracts, as in the Compositae. 



