margin, when dried the surface covered with small whitish lines (cystoliths), the 

 primary nerves rising from base and narrowly winged; flowers unisexual, green or 

 whitish, in axillary cymes to 3 cm. long; staminate flowers with 3 or 4 sepals 

 and stamens, often mixed with the pistillate flowers; calyx of pistillate flowers 

 deeply 3-parted, each of the unequal segments subtending a concave scalelike 

 staminodium; ovary free, with a sessile stigma; fruit a compressed thin-walled 

 achene that is subtended by the persistent calyx, ovate, pale green, smooth and 

 unspotted or with purple markings, 1.3-2 mm. long. Adicea pumila (L.) Raf. 



In moist or wet rich soils of woods, especially in seepage and along streams, 

 in e. Okla. (Cherokee Co.) and e. Tex., June-Nov.; from e. Can and N.E., s. to 

 Fla. and Tex., w. to S.D., la. and Kan. 



Most of our material is referable to var. Deamii (Lunell) Fern, which is more 

 southern in distribution than var. pumila, and has leaves more rounded at the 

 base and with 11 to 17 teeth on each margin, whereas the largest leaves of var. 

 pumila are mostly cuneate at the base and have only 3 to 11 teeth on each margin. 



Fam. 51. Polygonaceae Juss. Knotweed Family 



Caulescent or rarely acaulescent herbs or herbaceous vines; leaves alternate 

 or rarely opposite or whorled, the blades entire or rarely lobed or toothed; petioles 

 usually present; stipules (ocreae) present, usually sheathing the nodes, variously 

 long-sheathing or short-sheathing or sometimes deeply or shallowly lobed and some- 

 times fringed, rarely seemingly absent (Eriogonum; Brunnichia); flowers small, 

 hypogynous, perfect or unisexual, usually in racemes or in involucrate clusters, 

 sometimes solitary at the nodes; perianth of 2 to 6 usually nearly entirely separate 

 lobes, sometimes developing keels or wings, often coroUoid and whitish or pinkish; 

 stamens 2 to 9, the filaments often dilated basally; anthers 2-celled, each cell 

 with a longitudinal slit; ovary 1 -celled, usually trigonous (3-carpellate) or less 

 commonly lenticular (when one of the carpels is suppressed); styles 3 or 2, usually 

 not much united; ovule solitary, orthotropous; endosperm horny or mealy, usually 

 copious; fruit a trigonous or lenticular achene, usually falling still covered by the 

 remains of the calyx and androecium. 



A widely distributed family of about 35 conservative genera or upwards of 45 

 narrowly drawn ones. Some of the species are good honey plants. The Buckwheat, 

 Fagopyrum sagittatum Gilib., is a member of this family; it does not do well in 

 cultivation so far south as our region, but it has been grown in experimental plots. 



1. Vines with tendrils; endosperm ruminate 1. Brunnichia 



1. Herbs or if viny then tendrils absent; endosperm not ruminate (2) 



2(1). Leaf blades reniform; perianth 4-parted nearly to the base; pistil 2-carpel- 

 lary, the ovary strongly compressed 2. Oxyria 



2. Leaf blades never truly reniform, if cordate or hastate then the perianth 5- or 



6-lobed or -parted or the pistil 3-carpellary (3) 



3(2). Perianth segments usually 6, noticeably disparate in size, the outer ones not 

 enlarged, the 3 inner ones (valves) erect and greatly enlarged in 

 fruit (1 or more often with a dorsal callous grain); stigmas peltate, 

 tufted 3. Rumex 



3. Perianth segments usually 5, not greatly disparate in size at fruiting time; 



stigmas not tufted 4. Polygonum 



1. Brunnichia Gaertn. Eardrop Vine 



A monotypic North American genus. 



1. Brunnichia ovata (Walt.) Shinners. Fig. 398. 



Perennial vine; stems perennial at least in part, climbing by means of tendrils; 



795 



