Key to the Families 33 



Herbs. 



Petals 5 187. Hypericaceae. p. 671. 



Petals 4 105. Cruciferae, p. 484. 



D. Stamens just as many as or twice as many as the petals E. 

 E. Ovules and seeds only 1 or 2 in each cell. 

 Herbs. 



Flowers monoecious or dioecious 



147. Euphorbiaceae, p. 636. 



Flowers perfect and symmetrical. 



Cells of the ovary as many as the sepals. 



Ovary 2- or 3-celled 152. Limnanthaceae, p. 647. 



Ovary 5-celled 129. Geraniaceae, p. 623. 



Cells of the ovary twice as many as the sepals. 



Leaves abruptly pinnate 



135. Zygophyllaceae, p. 631. 



Leaves simple 132. Linaceae, p. 629. 



Trees or shrubs. 

 Leaves compound. 



Leaves 3-foliolate, punctate 4069. Ptelea, p. 632. 



Leaves pinnate, not punctate. . .165. Sapindaceae, p. 658. 

 Leaves simple. 



Blades palmately veined 163. Aceraceae, p. 654. 



Blades pinnately veined. 

 Leaves alternate. 



Shrubs, climbing 4625. Celastrus, p. 653. 



Shrubs, erect 157. Aquifoliaceae, p. 651. 



Leaves opposite 158. Celastraceae, p. 653. 



E. Ovules, and usually seed, several or many in each cell F. 

 F. Leaves compound. 



Trees or shrubs 161. Staphyleaceae, p. 654. 



Herbs; leaves alternate or all radical 



130. OXALIDACEAE. p. 626. 



F. Leaves simple. 



Stipules present between opposite leaves 



189. Elatinaceae, p. 677. 



Stipules none when the leaves are opposite. 

 Style 1. 



Stamens free from the calyx 233. Ericaceae, p. 733. 



Stamens inserted on the calyx. .216. Lythraceae, p. 695. 

 Styles 2-5 or splitting into 2 in fruit. 



Stamens free from the calyx; leaves opposite 



87. Caryophyllaceae, p. 435. 



Stamens inserted on the calyx.. 233. Ericaceae, p. 733. 

 v. Calyx tube adherent to the ovary, at least to its lower half G. 



G. Tendril-bearing and often succulent herbs. .275. Cucurbitaceae, p. 892. 

 G. Tendrils lacking H. 



H. Ovules and seed only 1 in each cell. 

 Stamens 5 or 10. 

 Trees or shrubs. 



Leaves simple, not prickly 3345. Crataegus, p. 533. 



Leaves compound or prickly 227. Araliaceae, p. 712. 



Herbs. 



Fruit dry, splitting at maturity; styles 2 



228. Umbelliferae, p. 714. 



Fruit berrylike; styles 2-5, separate or united 



227. Araliaceae, p. 712. 



Stamens 2, 4 or 8. 



Style and stigma 1; fruit a drupe 229. Cornaceae, p. 728. 



