14 KEY TO THE FAMILIES 



Stamens diadelphous. 51. Fumakiaceae 95 



Stamens monadelphous. 



Anther-sacs opening by slits; calyx and corolla regular. 



67. OXALIDACEAE 149 



Anther-sacs opening by pores; calyx and corolla very 



irregular. 73. POLYGALACEAE 150 



Filaments distinct. 



Corolla regular; anthers distinct. 



Herbaceous saprophytes, without green leaves. 



97. MONOTROPACEAE 174 



Herbs or shrubs with green leaves. 



Corolla of essentially distinct petals, i. e., united only 

 at the base; herbs with rootstocks. 



96. Pyeolaceae 174 



Corolla of distinctly united petals; shrubs. 



98. Ericaceae 174 

 Corolla irregular; one of the petals free; anthers united. 



69. Balsaminaceae 149 



2. Stamens partially adnata to the corolla. 



a. Stamens as many as the lobes of the corolla and opposite them, or 



twice as many or more; ovary 1-celled; placentae central or 

 basal. 100. Primdlaceae 176 



b. Stamens as many as the lobes of the corolla and alternate with 



them, or fewer. 



* Corolla not scarious, veiny; fruit various, but not a pyxis. 

 t Carpels distinct, except sometimes at the apex. 



Styles united: stamens distinct or gynandrous. 



105. Apocynaceae 181 

 Styles distinct; stamens monadelphous. 



106. Asclepiadaceae 183 



ft Carpels united. 



Ovary 1-celled, with central placentae. 



Corolla-lobes convolute or imbricated in the bud ; leaves 

 typically opposite and simple. 



103. Gentianaceae 179 

 Corolla-lobes induplicate-valvate in the bud; leaves al- 

 ternate, in ours mostly basal and trifoliolate. 



104. Mentanthaceae 181 

 Ovary 2-3-celled, or falsely 4-celled, or if 1-celled with 



parietal placentae. 

 Stamens 2, opposite to each other; corolla regular. 



101. Olbace.^e 179 

 Stamens usually more than 2, if only 2 not opposite to 



each other and the corolla irregular. 

 Leaves with stipules or stipular Unes. 



102. Loganiace.ae 179 

 Leaves without traces of stipules. 



Stamens 5, if only 3-4, not didynamous. 



Fruit a capsule or berry; ovary not 4-lobed. 

 Styles or stigmas usually distinct. 



Parasitic twining plants, with scale- 

 like leaves. 



108. Cuscutaceae 184 

 Plants not parasitic; leaves normal. 



Inflorescence not scorpioid; flowers 

 cymose or solitary ; ovary 2-3 

 celled. 

 Corolla plaited and the plaits 

 convolute in the bud; flow- 

 ers axillary, solitary or 

 cymose-conglomerate; plants 

 usually twining. 



107. Convolvdlaceae 183 

 Corolla merely convolute in the 



bud. not plaited; flowers 

 cymose: plants never twin- 

 ing. 



109. POLEM0NIACE.\E 184 



Inflorescence more or less dis- 

 tinctly scorpioid: ovary in 

 om's 1-celled or imperfectly 

 2-celled. 

 Fruit a capsule. 



110. Htdeophyllaceae 190 

 Fruit more or less drupaceous. 



111. Ehretiaceae 193 

 Styles and stigmas wholly united. 



Ovules few. 109. Convolvdlaceae 183 

 Ovules numerous. 



