112 



POLYGOXACEAE. 



1. Fagopyrum Fagopyrum 

 (L.) Karst. Buckwheat. (Fig. 

 130.) Annual, glabrous except at 

 the nodes, stem l°-3° high. Leaves 

 hastate, l'-3' long, abruptly nar- 

 rowed above the middle, acumi- 

 nate ; ocreae brittle and fugacious ; 

 racemes mostly panicled, some- 

 times corymbose, m.any-flowered, 

 erect or inclined to droop; pedicels 

 as long as the calyx; calyx-seg- 

 ments white or whitish; style- 

 branches deflexed in fruit ; achene 

 acute, 2i" long, about twice as 

 long as the calyx, its faces pin- 

 nately-striate when mature, the 

 angles acute, not crested. [Polyg- 

 onum Fagopyrum L. ; F. esculen- 

 tum Moench.] 



Fields and waste grounds, spon- 

 taneous after cultivation. Native of 

 Europe or Asia. Widely cultivated 

 for its edible grain, and considerably 

 grown in Bermuda. Flowers in 

 spring and summer. 



4. TINIARIA Eeichenb. 

 Annual or perennial unarmed slender vines. Leaves alternate, cordate or 

 hastate. Ocreae oblique. Eacemes loosely flowered, often paniculate. Sepals 

 5, green, white or yellowish, 2 exterior, 2 interior and 1 with one edge interior 

 and one edge exterior, this sepal and the two outer keeled or strongly winged. 

 Pedicels slender, reflexed and articulated. Stamens 8, included; filaments short, 

 converging. Styles 3, short or almost wanting, distinct or rarely united. 

 Achenes 3-angled, included, smooth and shining or granular and dull. Endo- 

 sperm horny. Cotyledons accumbent. [Latin, referring to the creeping habit.] 

 About 8 species, of North America and 

 Asia, the following typical. 



1. Tiniaria Convolvulus (L.) Webb. 

 & Moq. Black Bindweed. (Fig. 131.) 

 Annual, scurfy, dull green or pale green. 

 Stem prostrate or twining, 4'-3i° long, 

 the internodes of the older branches 

 greatly elongating; leaves ovate or 

 ovate-sagittate, V-2V long, acuminate at 

 the apex, cordate or truncate at the base, 

 somewhat undulate and crisped; ocreae 

 oblique, l"-2" long, acute; racemes 

 simple, loosely flowered, interrupted; 

 calyx green, at length 2" long, closely 

 investing the fruit; sepals oblong, ob- 

 tuse; stamens 8; achenes 3-angled, 

 obovoid or oblong-obovoid, short-tipped, 

 black. [Polygonum Convolvulus L.] 



Waste and cultivated grounds, uncom- 

 mon. Introduced. Widely naturalized in 

 North America. Native of Europe and Asia. 



