DESCRIPTIONS OF SOME COMMON WEEDS 137 



Ovary one ; 3 1 



30. Pollen in pollinia, stamens monadelphous (Asclepidaceae). P. 209. 

 Pollen not in pollinia (Apocyanaceae). P. 208. 



31. Ovary deeply four-lobed, leaves opposite (Labiatae). P. 218. 



Leaves alternate (Boraginaceae). P. 215. 



32. Fruit a berry (Solanaceae). P. 220. 



Fruit not a berry 33 



33. Ovary i 2-celled, seeds mucilaginous (Plantaginaceae). P. 225. 

 Ovary 2 3-celled, parasitic or twining, large or small flowers 



(Convolvulaceae). P. 210. 

 Ovary 2 3-celled, plants not twining 34 



34. Pod, many-seeded, styles two (Hydrophyllaceae). P. 214. 



Style i, branches or lobes of stigma 3 (Polemoniaceae). P. 214. 



35. Ovary four-lobed 36 



Not four-lobed 37 



36. Stamens inserted on the corolla tube, stem not four-sided, 



leaves alternate (Boraginaceae). P. 215. 

 Stamens not inserted on the corolla tube 38 



37. Ovary one-celled (Orobanchaceae). P. 225. 



Ovary one, pod two-celled (Scrophulariaceae). P. 223. 



38. Stamens united by their filaments, ovary one-celled (Com- 



positae). P. 229. 

 Stamens united by their filaments, ovary two or more celled. 



Corolla irregular (Lobeliaceae). 



Corolla regular (Gampanulaceae). P. 229. 

 Stamens not united by their filaments 39 



39. Ovary 2 5-celled leaves whorled, with or without stipules; 



fruit an indehiscent capsule (Rubiaceae). P 227. 

 Ovary 2 5-celled, leaves not whorled, but with small stipules 



(Caprifoliaceae). P. 228. 

 Ovary one-celled (Dipsaceae). 



Fern Family (Polypodiaceae). Plants with horizontal 

 rootstocks; leaves entire, pinnate, pinnatifid or decom- 

 pound; sporangia (spore cases) collected in dots (sori) 

 on the back of the frond, either covered with a mem- 

 branous indusium or naked ; sporangia from an incom- 

 plete, many-jointed ring. A large order of about 3,000 

 species of wide distribution, a few of which, like the shield 

 fern (Asplenium FilLv-mas), are used in medicine. 



Common Brake (Pteris aquilina, L.). A dull-green, 

 tough frond from a stout, black, woody rootstock; very 

 variable in height, varying from two to six feet; stipe 

 straw-colored or brownish ; branches of frond twice-pin- 

 nate; pinnules oblong-lanceolate, the upper undivided; 



