VOL. I. GENERAL KEY TO THE ORDERS AND FAMILIES. xxvii 



** Stamens usually very numerous (except in some Hypericaceae, in Elatinaceae, Violaceae and 



Passifloraceae) ; disk inconspicuous or none. 



t Sepals valvate; placentae united in the axis. Order 19. MALVALES. 



Stamens in several sets; anthers 2-celled ; embryo straight. Fam. 84. Tiliaceae. 2: 511. 



Stamens monadelphous ; anthers i-celled; embryo curved. Fam. 85. Malvaceae. 2:513. 



tt Sepals or calyx-segments imbricated or convolute (except in Loasaceae, in which the calyx-tube 

 is adnate to the ovary) ; placentae mainly parietal, sometimes united in the axis. 



Order 20. HYPERICALES (Parietales). 

 Sepals distinct, mostly persistent. 

 Endosperm little or none. 



Trees or shrubs with alternate leaves, and large solitary axillary flowers. 



Fam. 86. Theaceae. 2. : 526. 

 Herbs or low shrubs with opposite, rarely verticillate leaves. 



Leaves punctate or black-dotted, exstipulate. Fam. 87. Hypericaceae. 2 : 527. 



Leaves stipulate ; minute or small marsh or aquatic herbs with axillary flowers. 



Fam. 88. Elatinaceae. 2 : 537. 

 Endosperm copious. 



Flowers regular, but the 2 outer sepals smaller ; stamens numerous ; ovules orthotropous. 



Fam. 89. Cistaceae. 2 : 539. 

 Flowers irregular, some often cleistogamous ; stamens 5 ; ovules anatropous. 



Fam. 90. Violaceae. 2 : 545. 

 Sepals more or less united into a gamosepalous calyx. 



A fringed crown in the throat of the calyx ; our species vines ; stamens 5 ; ovary free from 

 the calyx. Fam. 91. Passifloraceae. 2:564. 



No crown ; our species herbs ; stamens numerous ; ovary adnate to the calyx. 



Fam. 92. Loasaceae. 2 : 565. 



II. Ovary inferior, adnate to the calyx, wholly, or in part (except in Lythraceae and our Melasto- 

 maceae, where it is usually merely enclosed by it, and in Thymeleaceae and Elaeagnaceae, 



which are shrubs or trees, with no corolla). 



1. Fleshy spiny plants, often with jointed stems, the leaves very small in our species, or none; 



calyx-segments and petals mostly numerous. 



Order 21. OPUNTIALES. 

 One family. 



Fam. 93. Cactaceae. 2:568. 



2. Herbs, shrubs or trees, not fleshy nor spiny ; calyx-segments and petals (when present) rarely 



more than 5. 



Petals none in our species; shrubs or trees; ovary i-ovuled. Order 22. THYMELEALES. 



Leaves green ; seed pendulous. Fam. 94. Thymeleaceae. 2:574. 



Leaves silvery-scurfy ; seed erect. Fam. 95. Elaeagnaceae. 2:575. 



Petals present (except in some Haloragidaceae, which are small aquatic herbs). 



Ovules several or numerous in each cavity of the ovary (except in Haloragidaceae and Trap- 

 aceae). Order 23. MYRTALES (Myrti florae). 



Land or marsh plants, or, if aquatic, submerged leaves not dissected. 



Calyx-tube merely enclosing the ovary, but free from it (except at the base). 



Anthers longitudinally dehiscent. Fam. 96. Lythraceae. 2 



Anthers opening by a terminal pore. Fam. 97. Melastomaceae. 2 



577- 

 582. 



584- 



Calyx-tube almost wholly adnate to the ovary. Fam. 98. Onagraceae. 2 



Aquatic or amphibious herbs, the submerged leaves dissected (except in Hippuris, which 



has whorled narrow leaves and only i stamen. 

 . Petioles of the broad floating leaves inflated ; flowers rather large, white. 



Fam. 99. Trapaceae. 2:611. 



Leaves most sessile ; petioles, if present, not inflated ; flowers small, greenish ; seeds 

 with i coat. Fam. 100. Haloragidaceae. 2:612. 



Ovules i in each cavity of the ovary. Order 24. UMBELLALES (Umbelli florae). 



Stamens 5 ; styles 2-5, rarely united ; flowers umbellate or capitate. 



Fruit a fleshy berry or drupe. Fam. 101. Araliaceae. 2 : 616. 



Fruit dry when mature, splitting into two mericarps. Fam. 102. Ammiaceae. 2: 619. 



Stamens 4 ; style i ; stigma i ; shrubs and trees ; flowers not umbellate. 



Fam. 103. Cornaceae. 2:660. 



Series 2. GAMOPETALAE. 



2 : 666 to 3 : 560. 



Petals more of less united. (See exceptions noted on page 666, Vol. 2.) 



A. Ovary superior (except in Vacciniaceae and Symplocaceae, in which it is partly or wholly 



inferior). 



I. Stamens mostly free from the corolla, or adnate merely to its base (at the sinuses of the corolla 

 in Diapensia and Pyxidanthera of the Diapensiaceae), as many as the lobes and 



alternate with them, or twice as many. Order i. ERICALES. 



Stamens free from the corolla, or merely adnate to its base, not united into a tube. 

 Ovary superior ; fruit a capsule, or rarely drupaceous. 

 Corolla essentially polypetalous. 



Ovary 3-celled ; shrubs; leaves deciduous. Fam. i. Clethraceae. 



Ovary 4-5-celled ; low, mostly evergreen perennials. Fam. 2. Pyrolaceae. 2 : 667. 



Corolla distinctly gamopetalous (except in Monotropa and Hypopitys of the Monotropaceae 



and Ledum of the Ericaceae). 



Herbaceous saprophytes without green leaves. Fam. 3. Monotropaceae. 



Shrubs with normal, often evergreen leaves. Fam. 4. Ericaceae. 



Ovary inferior, adnate to the calyx, forming a many-seeded berry in fruit. 



Fam. 5. Vacciniaceae. 2:694. 



