1836 



BIRTH WORT FAMILY. 



Aristolochia tomentosa Sims. 

 Woolly Pipe-vine. (Fig. 1284. ) 



i. tomentosa Sims, Bot. Mag. pi. 1369. 1811- 

 A twining vine, similar to the preceding, 

 it the twigs, petioles, leaves and pedun- 

 les persistently tomentose. Leaves sub- 

 rbicular or broadly ovate, obtuse or 

 junded at the apex, 3 / -6 / broad when 

 iture; petioles rather stout, \ f -$' long; 



luncles axillary, mostly solitary, slen- 

 sr, bractless; calyx densely tomentose, 

 ic tube sharply curved, yellowish green, 

 f long, its throat nearly closed, 

 ie limb becoming reflexed, wrinkled, 

 irk purple, 3-lobed; anthers contiguous 



pairs beneath the 3 spreading lobes of 

 ie stigma; capsule oblong-cylindric. 



In woods, Missouri and southern Illinois 

 North Carolina, Alabama and Florida. 

 ly-June. 



Family 14. POLYGONACEAE Lindl. Nat. Syst. Ed. 2, 211. 



BUCKWHEAT FAMILY. 



Herbs, twining vines, shrubs or trees, with alternate or sometimes opposite or 

 rfiorled simple mostly entire leaves, jointed stems, and usually sheathing united 

 tipules (ocreae). Flowers small, regular, perfect, dioecious, monoecious or 

 Dlygamous, spicate, racemose, corymbose, umbellate or panicled. Petals notfe. 

 ilyx inferior, free from the ovary, 2-6-cleft or 2-6-parted, the segmetr 

 spals more or less imbricated, sometimes petaloid, sometimes developing 

 rings in fruit. Stamens 2-9, inserted near the base of the calyx, or in stami- 

 ite flowers crowded toward the centre; filaments filiform or subulate, often 

 lilated at the base, distinct or united into a ring; anthers 2-celled, the sacs 

 jngitudinally dehiscent. Pistil solitary; ovary superior, i -celled; ovule soli- 

 orthotropous, erect or pendulous; style 2-3-cleft or 2-3-parted (rarely 

 ^-parted), sometimes very short; stigmas capitate or tufted, rarely 2-cleft; fruit 



lenticular 3-angled or rarely 4-angled achene, usually invested by the r* : 

 ent calyx; seed shaped like the pericarp; endosperm mealy; cotyledons accum- 

 bent or incumbent, flat; embryo straight or curved. 



About 30 genera and 800 species, of wide geographic distribution. 

 Flowers subtended by involucres. 



Ocreae present; calyx 2-4-parted; stamens 3 or fewer. 

 Ocreae none; calyx 6-cleft or 6-parted; stamens 9; achene 3-angled. 

 Flowers not involucrate; stamens 4-8. 

 Ocreae present; stigmas tufted. 



Calyx 6-parted; style 3-parted; achene 3-angled. 



Calyx 4-parted; style 2-parted; achene lenticular. 

 Ocreae present; stigmas capitate. 



Pedicels mostly several together; achene much surpassing the calyx. 



Pedicels usually fascicled; achene mostly enclosed by the enlarged calyx. 6. PMyg< 



Pedicels solitary; leaves jointed at the base. 



8. 



:< >tf unii HI. 



3- Kit 



. 



'HIM. 



Ocreae obscure or wanting; stigmas 2-cleft. 





i. MACOUNASTRUM Small. 

 [KOENIGIA L. Mant. 35. 1767. Not Konig Adans. 1763.] 



Low glabrous annual herbs, with fibrous roots, erect or spreading simple or fot> 

 alternate or opposite entire leaves, funnelform membranous ocreae, and minute perfect ter- 

 minal clustered flowers, subtended by a several-leaved involucre. Calyx 2-4-parted (usually 

 3-parted), greenish-white, the segments valvate, eejual; pedicels short, subtended by trans- 

 parent bracts; stamens 2 or 4, alternate with and often protruding between the calyx-seg- 

 ments; filaments short, stout; anthers ovoid. Style 2-3-partcd; stigmas capitate; 

 ovoid, 3-angled or lenticular, exceeding the persistent calyx; embryo eccentric, accutnbent. 



Two or three species, the following circumboreal, the others of the higher Himalayas. 



*Text contributed by Dr. JOHN K. SMALL. 



