260 ERIOCAULACEAE (PIPEWORT FAMILY) 



4. L. minor L. Fronds round- to elliptic-obovate (2-5 mm. in diameter), 

 rather thick, very obscurely 3-nerved; spathe sac-like; utricle short-urn-shaped, 

 tipped with a short style ; seed oblong-obovate, amphitropous, with prominent 

 rounded operculum. Stagnant waters, except along our n. borders. (Temp, 

 regions.) 



3. W6LFFIA Horkel. 



Flowers central, bursting through the iipper surface of the globular (or in 

 some foreign species flat) and loosely cellular frond, only 2 ; one consisting of a 

 single stamen with a 1-celled 2-valved anther ; the other of a globular ovary, 

 tipped with a very short style and a depressed stigma. Ovule orthotropous, 

 rather oblique in the cell. Utricle spherical. Albumen thin. Fronds root- 

 less, proliferous from a cleft or funnel-shaped opening at the base, the offspring 

 soon detached; no rhaphides. The simplest and smallest of flowering plants, 

 floating as little grains in or on the water. (Named for Johann Friedrich Wolff, 

 who wrote on Lemna in 1801.) 



Not dotted; upper surface strongly convex 1. W. columbiana. 



Dotted. 



Upper surface flattish 2. W. punctata. 



Upper surface low-conical 3. W. papulifera. 



1. W. columbiana Karst. Globose or globular, 0.7-1.5 mm. long, very 

 loosely cellular, light green all over, not dotted ; stoinata 1-6 ; the opening at 

 the base circular and with a thin border. Floating rather beneath the surface 

 of stagnant waters, Ct. to Fla.. w. to Minn, and La. 



2. W. punctata Griseb. Oblong, smaller and more densely cellular, flattish 

 and deep green with many stomata above, tumid and pale below, brown-dotted 

 all over, anterior edge sharp ; opening at base circular. ( W. brasiliensis of 

 auth., not WeddelL) Ont. to the Gulf of Mex. Growing with the preceding 

 but floating on the surface. 



3. W. papulifera C. H. Thompson. Lower surface hemispherical, the upper 

 flattish at the margin, rising at the center to a single low papilla ; flowers 

 unknown. Mo. (Bush, Thompson). 



4. WOLFFIELLA Hegelm. 



Flowers and fruit unknown. Fronds (in ours) linear-attenuate or flagellate, 

 falcate or sigmoid, many times longer than wide, punctate, solitary or cohering 

 at the base and radiating in a stellate manner. Pouch single, triangular, basal. 



Small genus of imperfectly known plants. (Name a diminutive of Wolffia ^ 

 1. W. floridana (J. D. Sm.) Thompson. Fronds hollow, gradually attenuate 



from base to flagellifonn apex, 6-8 mm. long. ( Wolffia gladiata, var. J. D. Sm.) 



Mo. to Fla. and Tex. 



ERIOCAULACEAE (PIPEWORT FAMILY) 



Aquatic or marsh herbs, stemless or short-stemmed, with a tuft of fibrous 

 roots, a cluster of narrow and often loosely cellular grass-like leaves, and nakfd 

 scapes sheathed at the base, bearing dense heads of monoecious or rarely 

 dioecious small "2 3-merous flowers, each in the axil of a scarious bract; the 

 perianth double or rarely simple, chaffy; anthers introrse ; the fruit a 2-3- 

 ce lied 2-3-seeded capsule ; seeds pendulous, orthotropous ; embryo at the apex 

 of mealy albumen. Chiefly tropical plants, a few in northern temperate regions. 



1. Eriocaulon. Perianth double, the inner (corolla) tubular-funnel-form in the staminate 



flowers. Stamens twice as many as the corolla-lobes (4). Anthers 2-celled. 



2. Syngonanthus. Perianth as in the last. Stamens only as many as the corolla-lobes (8). An- 



thers 2-celled. 



3. Lachnocaulon. Perianth simple, of 8 sepals. Stamens 8. monadelphous below. Anthen 



1-celled. 



