KEY TO THE ORDERS. XIX 



CONVOLVULACE^. — Style 2-cleft. Pod 2-celled, generally 

 4-seeded ; seeds large. Chiefly twining or trailing 

 plants 17,^ 



SolanacEjE. — Style single. Pod or berry 2-celled, many- 

 seeded 174 



* * * * Stamens fewer than the lobes of the corolla ; the 

 corolla mostly irregvlar or ^-lipped. 



L.yeiaTjE. — Ovary 4-lobed around the base of the style. 



Stameus 4 and didyuamous, or occasionally only 



2 with anthers. Stem square 160 



Verbenace^. — Ovary 4-celled, but not lobed ; the style 



rising from the apex. Or,. Ovary 1-oeIled and 1- 



seeded. Stamens didynamous 158 



Lentibttlakiace^. — Aquatics. Stamens 2. Ovary 1- 



celled, with a free central placenta 149 



Orobanchace^ — Parasitic herbs, without green foliage. 



Ovary 1-celled, with many seeds on the walla. 



Stamens didynamous 150 



ScB.OPHULAKiACE.1:. — Ovary 2-oelIed, with many seeds. 



Stamens didynamous, or only 2 151 



AcANTHACE^. — Stamens 2, the anther-cells separated. 



Ovary flat, 2-celled, 4-seeded. Aquatics 159 



ni. APETALOUS DIVISION. 

 Corolla (and sometimes calyx also) wanting, 



A. FloiY'ers not in catkins. 



* Calyx and corolla both wanting. 



PlPERACE^. — Flowers white, in a, dense terminal spike, 

 nodding at the end. Carpels 6 or 4, nearly separ- 

 ate 182 



Ceratophyt.t.acej:. — Immersed aquatics, with whorled 



finely dissected leaves. Flowers monoecious .... 213 



* * Calyx superior (i. e. , adherent to the ovary). 



SAXiFRAeACE^. — Small, smooth herbs, with inqonspicaons 

 greenish-yellow flowers. Stamens twice as many 

 as the calyx-lobes, on a conspicuous disk 75 



Halokage^. — Aquatics. Leaves finely dissected or linear. 



Stamensl-8. Ovary3-4-lobedor(Hippuris)l-celled. 79 



On^ageace^. — Herbs, in ditches. Stamens 4. Ovary 4- 



celled, 4-sid6d 81 



