Vol. I. GENERAL KEY TO THE ORDERS AND FAMILIES. xxix 



Opposite-leaved herbs; capsule i -celled in our genus; seeds wingless. 



Fam. 32. Martyniaceae. 3 : 239. 



XX Capsule completely 2-celled, elastically loculicidally dehiscent ; opposite-leaved herbs ; placentae 



axile. 



Fam. 33. Acanthaceae. 3 : 239. 

 3. Ovary and fruit i-celled with 1 erect orthotropous ovule and seed; herb with spicate flowers 



and reflexed fruits. 



Fam. 34. Phrymaceae. 3 : 244. 

 ** Corolla scarious, nerveless. 



Order 6. Plantaginales. 

 Herbs with small spicate or capitate flowers ; one family. Fam. 35. Plantaginaceae. 3 : 245. 



B. Ovary inferior. 



I. Anthers distinct. 

 Stamens as many as the corolla-lobes and alternate with them (one fewer in Linnaea of the Capri- 

 foliaceae), or twice as many; ovary compound, with 1 ovule or more in each cavity; leaves 

 opposite, or verticillate. Order 7. Rubiales. 



Stamens as many as the corolla-lobes. 



Leaves always stipulate, usually blackening in drying. Fam. 36. Rubiaceae. 3 : 250. 



Leaves usually exstipulate, not blackening in drying. Fam. 37. Caprifoliaceae. 3 : 267. 



Stamens twice as many as the corolla-lobes ; low herb with ternately divided leaves. 



Fam. 38. Adoxaceae. 3 : 283. 



Stamens mostly fewer than the corolla-lobes; ovary i-celled with 1 pendulous ovule, or 3-celled with 



2 of the cavities without ovules. Order 8. Valerianales (Aggregatae). 



Ovary 3-celled, 2 of its cavities empty. Fam. 39. Valerianaceae. 3 : 284. 



Ovary i-celled; flowers densely capitate, involucrate. Fam. 40. Dipsacaceae. 3:288. 



II. Anthers united (except in Campanula and Specularia of the Campanulaceae, in Ambrosiaceae, 



and in Kuhnia of the compositae). Order 9. Campanulales (Campanulatae). 



Flowers not in involucrate heads ; juice mostly milky. 



Endosperm none ; flowers monoecious or dioecious ; our species vines. 



Fam. 41. Cucurbitaceae. 3:290. 

 Endosperm present, fleshy ; flowers perfect. 



Flowers regular. Fam. 42. Campanulaceae. 3 : 293. 



Flowers irregular. Fam. 43. Lobeliaceae. 3 : 299. 



Flowers in involucrate heads. 



Flowers all expanded into rays (ligulate) ; juice milky. Fam. 44. Cichoriaceae. 3 : 304. 



Flowers all tubular, or the outer expanded into rays ; juice very rarely milky. 



Stamens distinct, or nearly so. Fam. 45. Ambrosiaceae. 3: 338. 



Stamens united by their anthers into a tube around the style (except in Kuhnia). 



Fam. 46. Compositae. 3 : 347. 



