512 PHARMACEUTICAL BOTANY 
OrrictAL Druc Part Usep BoTANICAL ORIGIN HABITAT 
Aristolochia 
Serpentaria Rhizome and roots Bers ania United States 
Aristolochia 
reticulata 
Asarum Rhizome and roots Asarum canadensis United States 
OrDER POLYGONALES 
PoLyGonace® Famrty.—Usually herbs [Knot-grasses (Poly- 
gonum), rhubarb (Rheum), docks (Rumex), buckwheat (Fagopy- 
Fic. 382.—Serpentaria—Cross-section of rhizome. (25 diam.) A, parenchyma 
of cortex; B, medullary ray; C, xylem; D, phloem; FE, medulla. (Sapre.) 
rum), etc.| rarely trees (Coccoloba uvifera or Sea-Grape) or shrubs 
(Muehlenbeckia or Ribbon Bush) having strong vertical tap roots 
and ‘Spreading secondary roots more or less provided with 
tannin compounds. Stems elongate, green, to woody, rarely 
flattened, leathery, phylloidal (Muehlenbeckia platyclada), still 
more rarely tendriliform (Antigonon leptopus or Mountain Rose 
of Tropical America). Leaves alternate, rarely opposite or 
_whorled (Eriogonum), entire, rarely lobed (Rheum palmatum, 
Rumex acetosella), petiolate, rarely sessile, and stipulate. Stipules 
fused and forming a greenish membranous upgrowth (ocrea) 
_ which sheaths the stem. Inflorescence racemose with many 
dense scorpioid or helicoid cymes, which in some forms condense 
into single flowers. Flowers regular, pentamerous, with simple 
calyx, becoming trimerous with two whorls of three sepals each. 
Stamens varying from fifteen or twelve to nine or six, more 
