272 ASCLEPIADACEAE. 



Corolla plaited and the plaits convolute in the bud ; flowers axillary, 

 solitary or cymose-conglomerate ; plants usually twining. 



112. CONVOLVULACEAE. 



Corolla merely convolute in the bud, not plaited ; flowers cymose ; 

 plants never twining. 113. Polemoniaceae. 



Inflorescence more or less distinctly scorpoid ; ovary in ours i-celled or 

 imperfectly 2-celled ; micropyle of the seed turned upwards. 



114. Hydroleaceae. 

 Styles and stigmas wholly united. 



Ovules few. 112. Convolvulaceae. 



Ovules numerous. 



Median axis of the gynoecium in the same plane as the axis of the 



stem; seeds mostly pitted. 119. Solan aceae. 



Median axis of the gynoecium not in the same plane as the axis of the 

 stem; seed tuberculated (Verbascum). 120. Rhinanthaceae. 



Fruit of 1-4 nutlets (in all our genera) ; ovary more or less distinctly 4-lobed. 

 Style or stigma furnished with a glandular ring. 115. Heliotropaceae. 



Style or stigma not furnished with a glandular ring. 116. Boraginaceae. 

 Stamens 4 and didynamous, or 2 or i. 



Carpels ripening into 4 nutlets, an achene or a drupe. 



Style apical on the lobeless ovary. 117. Verbenaceae. 



Style arising between the 4 lobes of the ovary. 118. Laminaceae. 



Carpels ripening into a capsule. 

 Placentae of the ovary axile. 



Ovary 2-celled, rarely 3-5-celled ; land-plants. 120. Rhinanthaceae. 



Ovary i-celled; ours submerged water-plants. 121. Pinguiculaceae. 



Placentae of the ovary parietal. 



Herbs parasitic on the roots of other plants ; leaves scale-like, not green. 



122. Orobanchaceae. 

 Herbs with green leaves ; not parasitic. 123. Martyniaceae. 



Family 1 1 1 . CUSCUTACEAE Dumont. Dodder Family. 



I. CUSCUTA L. Dodder. 



Styles equal with elongated stigmas. 1. C. epithymum. 



Styles unequal ; stigma capitate. 



Capsules circumscissile ; calyx- and corollarlobes acuminate ; inflorescence um- 

 bel-like, i:. C. umbellata. 

 Capsule indehiscent or bursting irregularly. 

 Calyx gamosepalous, usually not bracted. 

 Corolla-lobes not incurved. 



Scales of the corolla incurved upon the ovary ; styles about half as long 



as the ovary or longer. 3. C. Gronovii. 



Scales of the corolla appressed to the corolla-tube ; styles }4-/^ ss long 

 as the ovary. 4. C. curta. 



Corolla-lobes incurved at the apex. 



Capsule 4 mm. or less broad ; inflorescence rather open. 



5. C. indecora. 

 Capsule 5-6 mm. broad ; inflorescence globular clusters. 



6. C. megalocarpa. 

 Calyx of 5 almost distinct and overlapping sepals, subtended by 2 or more 



similar bracts. 7. C. cuspidata. 



1. Cuscuta epithymum L. On clover, alfalfa, etc. ; introduced from Eu- 

 rope. — Ft. Collins. 



2. Cuscuta umbellata H. B. K. On low herbs, especially on Portulaca, 

 from Colo, to Tex. and Ariz.; also in Mex. — Hovenweep Canon (Brdndegee). 



3. Cuscuta Gronovii Willd. On low shrubs and coarse herbs from N. S. 

 and Man. to Fla., Tex. and Colo. — Manitou. 



