108 POLYGON ACE AE. 



Sepals white, 5, unchanged at maturity. Stamens 5-8: filaments filiform. 

 Stigmas 3. Achene 3-angled, exserted. 



1. F. Fagopyrum (L.) Karst. Stem 1-9 dm. tall, slightly pubescent about the 

 nodes: leaf -blades hastate, 2.5-8 cm. long: panicles persistently flowering: 

 sepals becoming 2.5-3 mm. long: achenes 5-6 mm. long. Occasional, in fields 

 and on roadsides. Nat. of Eu. Sum. BUCKWHEAT. 



6. TBACAULON Kaf. Annual or perennial, prickle-armed, reclining- 

 climbing herbs. Leaves alternate, not jointed at the oblique ocreae. Flowers 

 borne in spike-like or capitate panicles. Sepals often slightly colored, 5 or 4, 

 neither keeled nor winged. Stamens 5-8: filaments slender. Stigmas 2 or 3. 

 Achene lenticular or 3-angled, included. Sum. TEAR-THUMB. 



Leaf-blades sagittate : achenes 3-angled. 1. T. sagittatum. 



Leaf -blades hastate : achenes lenticular. 2. T. arifolium. 



1. T. sagittatum (L.) Small. Leaf -blades lanceolate to oblong, 1-12 cm. long, 

 the basal lobes acute: ocreolae 3-5 mm. long: sepals becoming 4 mm. long: 

 stamens 8 : achenes 3-3.5 mm. long. Common, in wet places and meadows. 



2. T. arifolium (L.) Raf. Leaf -blades hastate, 2-18 cm. long, the basal lobes 

 spreading, acuminate: ocreolae about 2 mm. long: sepals becoming 4 mm. 

 long: stamens 6: achenes 4 mm. long. Common, in wet thickets and meadows. 



7. TINIARIA Eeichenb. Annual or perennial, unarmed twining vines. 

 Leaves alternate, not jointed at the oblique ocreae. Flowers borne in branch- 

 ing raceme-like panicles or in axillary clusters. Sepals white or yellowish, 5, 

 the outer ones keeled or winged at maturity. Stamens 8: filaments slender. 

 Stigmas 3. Achenes 3-angled, included. Sum. and fall. 



Outer sepals keeled at maturity : achene granular and dull. 1. T. Convolvulus. 

 Outer sepals developing conspicuous wings : achene smooth and 

 shining. 



Sepal-wings not incised : achenes over 3.5 mm. long. 2. T. scandens. 



Sepal-wings incised : achenes less than 3.5 mm. long. 3. T. cristatum. 



1. T. Convolvulus (L.) Webb. & Moq. Stem and branches trailing or twin- 

 ing, green or purple-tinged: leaf -blades ovate to ovate-sagittate, or those of 

 the upper ones sagittate, 1.5-6 cm. long: ocreae rough-edged: sepals mealy- 

 granular, the outer becoming longer than the inner: achenes about 3.5 mm. 

 long. Common, in moist places and fields. Nat. of Eu. BLACK-BINDWEED. 



2. T. scandens (L.) Small. Stem* and branches twining, purplish: leaf- 

 blades ovate to oblong-ovate, 4-12 cm. long: ocreae with rough ridges: mature 

 hypanthium and calyx 12-15 mm. long: achenes 4-4.5 mm. long. Common, 

 in thickets and fence-rows. HEDGE-BUCKWHEAT. FALSE-BUCKWHEAT. 



3. T. cristatum (Engelm. & Gray) Small. Stem and branches twining, green 

 or purplish: leaf -blades ovate to triangular, 1-6 cm. long: mature hypanthium 

 and calyx 6.5-7.5 mm. long: achenes 3 mm. long. Lower Susquehanna valley. 

 Bather common, on river banks. 



Order CHENOPODIALES. 



Herbs, often partially woody, or shrubs, or trees. Leaves alternate 

 or opposite, occasionally scale-like. Flowers mostly perfect, sometimes 

 monoecious or dioecious. Calyx usually present, the sepals mainly sepa- 

 rate. Corolla wanting, or present and of minute or large petals. Androe- 

 cium of 1-several stamens. Gynoecium a single carpel or of several united 



