X GENERAL KEY TO THE ORDERS AND FAMILIES. 



2. Calyx present. 

 ^ Flowers, at least the staminate ones, in amenta. Order 5. FagalES. 

 Both staminate and pistillate flowers in aments. Fara. 6. liiltilaceac. 1:506. 



Pistillate flowers subtended by an involucre, which becomes a bur or a cup in fruit. 



Fam. 7. Fagaceae. 1: 513. 

 ■K- -X- Flowers not in aments (in ament-like spikes in Aforiis), but variously clustered, rarely solitary, 

 a. Flowers monoecious, dioecious or polyg;amous (sometimes perfect in Ulnius); 

 ovary superior, i -celled. Order 6. Urticales. 



Fruit not an achene: trees, shrubs or herbs; ovule pendulous. 



Trees with alternate leaves, the sap not milky. Fam. S. Ulmaceae. i: 523. 



Trees with alterniitc leaves and milky sap; or opposite-leaved herbs or herbaceous vines. 



Fam. 9. ^[oraccae. i: 527. 

 Fruit an achene; herbs with small clustered greenish flowers; ovule erect or ascending. 



Fam. 10. Urticaceae. 1: 530. 

 (Order 7, Proteales, extensively developed in the southern hemisphere, is not represented iti 

 our area. ) 



b. Flowers dioecious, or perfect; ovary inferior, at least in part. 

 Ovary i-celled. Order 8. S.vntalales. 



Tree-parasites, with opposite leaves or scales; fruit a berry. Fam. 11. Lorantliaccac. 1:534. 



Root- parasites, or shrubs; leaves alternate in our genera; fruit a drupe, or nut. 



Fam. 12. Sanlalaceae. 1:536. 

 Ovary several- (usually 6") celled; flowers perfect. Order 9. Aristolochiales. 



One family in our area. Fam. 13. Arhlolocliiaccae. 1:537. 

 C. Flowers mostly perfect incur genera (dioecious in some species of Rumcx in Polygonaceae, 

 monoecious or dioecious in some Chenopodiaceae and Amaranthaceae); ovary superior. 

 t Embryo straight, or nearly so; fruit an achene. Order 10. Polv(;o.n"ales. 



One family. Fam. 14. Polygonaceae. 1:541. 



t t Embryo coiled, ctirved, or annular; fruit not an achene. 



Order II. Che.noPouiale.s (Ccnirospermae). 

 Fruit a utricle (see also last genera of Caryophyllaceae ). 



Flowers bractless, or, if bractcd, the bracts not scaiious; sepals green, or greenish. 



Fam. 15. Chenopodiaceae. i: 569. 

 Flowers bracted, the bracts, and also the sepals mostly scarions. 



Fam. 16. Amaranlhaceae. 1:586. 

 Fruit fleshy, enclosing several carpels: a berry. Fam. 17. Pliylolaccaceae. 1:593. 



Fruit an anthocarp, the persistent base of the corolla-like calyx enclosing a utricle. 



Fam. iS .Xi'clagiiiaceae. 1: 594. 

 Fruit a capsule, dehiscent by valves, or teeth (utricular in Anychia, Paronychia and Sclcranthus 

 of the Caryophyllaceae). 

 Capsule a-several-celled: petals none. Fam. 19. Aizoaccae. 1:597. 



Capsule i-celled; petals mostly present. 



Sepals 2. Fam. 20. Porlulacaaae.i: i. 



Sepals 5 or 4, distinct or united. Fam. 21. Caryophyllaceae. 1: 6. 



B. Petals present (wanting in Ceratophyllaceae — aquatic herbs with whorled dissected leaves; in. 

 many Raiuinculaceae; in Catvaicarpum — a dioecious vine of the Menispermaceae; in Laura- 

 ceae — alternate-leaved aromatic trees and shrubs; in Podostemaceae — aquatic herbs, the sim- 

 ple flowers involucrale; in Liquidamhar — a tree, with palmately-lohed leaves and capitate 

 flowers of the Hamamelidaceae: in Sanguisorha — herbs with pinnate leaves of the Rosaceae; 

 in .Xanlhoxvluni — trees with pinnate leaves of the Rutaceae; in EuphorbiaceaL-; in Callitrich- 

 aceae, Empetraceae and Kuxaceae; in some of the .■\ceraceae and Rhaninaceae; in Thymelc- 

 aceae, Elaeagnaceae, and in some species of Lud-.iigia in Onagraceae and of Xyssa in Cor- 

 naceae). 



I. Ovary superior, fn, from the calyx (partly or wholly inferior in some Saxifragaceae, 

 in Grossulariaceae, Hamamelidaceae, Pomaceae and Loasaceae). 



I. Carpels solitary, or several or distinct (united in some Nymphaeaceae); stamens mostly hypogynous 



and more numerous than the sepals ; sepals mostly distinct. Order 1 2. R.\nales. 



-:v Aquatic herbs ; floating leaves peltate, or with a basal sinus. 



Carpels 3, or more; petals large; floating leaves not dissected. Fam. 22 .Xymphaeaceae. 2:41. 



Pistil I; petals none; leaves whorled, all submersed and dissected. Fam. 23. Ceratophyllaceae. 3:46. 



■K- -K- Land or marsh plants (some Ranunculaceae aquatic^ 

 Stamens numerous; sepals distinct; petals present (except in some Ranunculaceae and in Calyco- 

 carpinn of the Menispermaceae). 

 Receptacle not lu)llow; lea\'es alternate (except in Clewalis). 



Flowers perfect (except in some species of Clematis and Thaliclrum). 



Fruit aggregate, cone-like; trees; sepals and petals in 3 series, or more, of 3. 



Fam. 24. J/agnoliaceae. 2: 47. 

 Fruit not aggregate, the carpels separate, at least when mature. 

 .\nthers not opening by valves; pistils usually more than i. 



Sepals 3; petals 6; shrubs or trees. Fam. 25. Anonaceae. 2:49. 



Sepals 3-15: petals (when present) about as many; our species herbs or vines 

 ( .\'<7H//;o/>7;;;« .shrubby V Fam. 26. Ranunculaceae. 2:50. 



Anthers opening by valves (except in Podophyllum i; pistil i 



Fam. 27. Berberidaceae. 1: 89. 

 Dioecious climbing vines with simple leaves; fruit drupaceous. 



Fam. 28 Menispermaceae. 2: 93. 

 Receptacle hollow, enclosing the numerous pistils and achenes; opposite-leaved shrubs. 



Fam 29. Calycanthaeeae. 2: 94. 



Stamens 9 or 12, in 3 or 4 series of 3- anthers opening by \-alves; aromatic trees or shrubs with no 



petals, more or less united sepals, and i pistil. Fam. 30. Lauraceae. 2: 95. 



