178 RUBIACEAE 



oylindric : flowers subdioecious : capsule 2-seeded. Common in dry 

 grounds and waste places. April-June. 



7. P. elongata Pursh. Puberulent annual, l / -4 / high : spikes 

 slender : flowers subdioecious : stamens only two : capsule 4-seeded. 

 Locally common on sterile prairies from Lee's Summit to Greenwood, 

 and in dry woods near Grain Valley. April-May. 



FAMILY 118. EUBIACEAE B. Juss. 



Plants with opposite or verticillate usually stipulate leaves and per- 

 fect, regular, nearly symmetrical flowers. Calyx coherent with the 1-10- 

 celled ovary. Corolla gamopetalous, 4-5-lobed, variously shaped. Stamens 

 inserted on the corolla and alternate with its lobes. Ovules 1-many in 

 each cell of the ovary. Fruit various. 



Leaves opposite. 



Herbs : ovary with many ovules. 1. HOUSTONIA. 



Shrubs. 2. CEPHALANTHUS. 



Herbs : ovary with two ovules. 3. DIODIA. 



Leaves verticillate. 4. GALIUM. 

 1. HOUSTONIA L. 



Calyx tube 4-lobed. Corolla funnel-form or salver form, 4-lobed. 

 Stamens four. Style one. Stigmas two. Upper half of the 8-40-seeded 

 capsule fiee from the calyx. Flowers dimorphous. 



1. H. minima Beck. BLUETS. Annual, spreading, 2 / -5 / high, sca- 

 brous : leaves oblong-oval, short-petioled : corolla purplish. On prairies 

 and in dry woods, Little Blue Tank, Lee's Summit, Greenwood, Grain 

 Valley. April. 



2. CEPHALANTHUS L. 



Flowers white, in dense spherical heads. Calyx limb 4-lobed. Corolla 

 funnel-form, shortly 4-lobed. Stamens four, short. Styles one. Stigmas 

 two. Fruit dry, obpyramidal, 1-2-seeded. 



i. C. occidentalis L. BUTTON BUSH. 3-15 high : leaves ovate, 

 petioled, entire : heads l x in diameter. Swampy grounds throughout. 

 Locally common. June-August. 



3. DIODIA L. 



Herbs with conspicuous stipules and small axillary flowers. Calyx 

 limb 4-lobed (in ours). Corolla funnel-form or salver-form, 4-lobed. 

 Stamens four. Fruit of two indehiscent 1-seeded carpels. 



1. D. teres Walt. BUTTON WEED. Annual, erect, spreading, 3 X -15 X 

 high, rough : leaves linear-lanceolate, entire : style entire. Adventized 

 jn waste places near Hickman's Mills, Sheffield and Lee's Summit. 

 July-September. 



4. GALIUM L. 



Herbs with square stems, whorled leaves and small white flowers. 

 Calyx teeth four, or obsolete. Corolla 4- or 3-lobed. Stamens four or 

 three. Styles two. Ovary 2-celled, 2-ovuled. Fruit of two indehiscent 

 carpels. 



