KEY TO THE ORDEES. xix 



CoNvo\jVtrLACE^.— Style 2-oleft. Pod 2-oelled, generally 

 -, 4-seeded ; seeds large. Chiefly twining or trailing 



yplants 173 



SOLANACE^, — Style single. Pod or berry 2-oelled, many- 

 seeded 174 



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

 corolla mostly irregular or ^-lipped. 



Labiate. — Ovary 4-lobed around the base of the style. 



Stamens 4 and didynamou^, 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 -celled and 1- 



seeded. Stamens didynamons 15S 



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



celled, with a free central placenta 149 



OkobanchacEjE — Parasitic herbs, without green foliage. 



Ovary 1 -eel led, with many seeds ou the walls. 



Stamens didynaihous 150 



ScROPiiULARiACE^. — Ovary 2-oelled, with many seeds. 



Stamens didyuamous, or only 2 151 



AcANTHACEiE. — Stamens 2, the anther-cells separated. 



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



III. APETALOUS DIVISION. 

 Corolla (and sometimes calyx also) wanting. 



A* Floivei's not in calkins. 



* Calyx and corolla both wanting, 



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

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

 ate 182 



CEBATorHTLLACE^. — Immersed aquatics, with whorled 



jinely dissected leaves. Flowers moncEoious 213 



* * Calyx superior (i.e., adherent to the ovary y.~~'/ 



■ Saxifbagace.e. — Small, smooth herbs, with inconspicuous 

 greenish-yellow flowers. Stamens twice as many 

 as the calyx-lobes, ou a conspicuous disk 75 



Halorage.*;. — Aquatics. Leaves finely dissected or linear. 



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



Onagbace.e. — Herbs, in ditches. Stamens 4. Ovary 4- 



celled, 4-sided ■.>-\i- ^1 



