Milkweed Family. 107 



APOCYNUM L. Bark fibrous. Leaves inucronate-pointed. Calyx si- 

 parted. Corolla eampanulate, "5-cleft. Stamens included, attached to the 

 base of the corolla; anthers sagittate, longer than the filaments. Follicles 

 separate, slender; seeds with a tuft of silky hairs at the apex. 



A. androsaemifolium L. Dogbane. Stem 3-3 feet high, mostly glabrous 

 branches divergent; leaves ovate, downy beneath, short-petioled; flowers in 

 spreading cymes, terminal or lateral; corolla rose red, tube longer than the 

 calyx. Fields and waste places; June-July; f,requent throughout the state. 



A. cannabinum L. Indian Hemp. Stem 2-4- feet high, glabrous to soft- 

 pubescent; branches ascending; leaves sessile, oval to oblong, base somewhat 

 cordate; cymes terminal; corolla greenish white, tube about the length of 

 the calyx-lobes. Rich soil; July-August; frequent. 



A. pubescens R. Br. Whole plant densely velvety-pubescent; leaves oval 

 to elliptic, obtuse or acute, mueronate; cymes dense. Reported from Ulack- 

 hawk county by Arthur. According to Britton and Brown this species was 

 collected by Dr. C. C. Parry in Polk county in the year 18(17. 



A.SCLEPIADACEAE Li mil. Milkweed Family. 

 Herbs, usually with milky juice, and opposite, whorled or scattered, 

 ent|re exstipulate leaves. Flowers in some form of an umbel, regular, 

 parts in 5's, sepals and petals valvate in the bud. Stamens 5. adhering 

 to and coverinu- the 2 stiuraas. 



Asci.epias. Hoods provided with horns. 

 Acerates. Hoods destitute of horns. 



ASCLEPIAS L. Milkweed. Perennials. Calyx persistent. 5-partetl. re- 

 flexed. Corolla fi-parted, deciduous, valvate in the bud, reflexed. Crown 

 made up of .Vhooded bodies, each with an incurved horn. Stamens inserted 

 on the base of the corolla; anthers consolidated with the stigma, tipped with 

 a membranaceous appendage, 2-celled, each containing » suspended waxy 

 pollen mass, the pollinia. those of each anther forming pairs. Ovaries 2, 

 developing into 1 or 2 follicles. Seeds flat, with a tuft of silky hairs at one 

 end. 



* Leave* opposite or alternate; corolla anil corona orange. 



A. tuberosa D. Butterfly- weed. Root tuberous; stem 1-2 feet high; juice 

 not milky; roughish-hairy, leafy, branching near the top; leaves alternate, 

 sessile or shoit-petioled, linear or lance-oblong; umbels many, erect, cor- 

 ymbed: flowers scarlet. Fields; June-July; common. 



A. decumbens L. Stems decumbent, 2-3 feet long, hirsute-pubescent; 

 leaves oblon" or elliptic, obtuse, short-petioled or sessile, mostly opposite; 

 umbels from the upper axils; corolla dark orange; follicles slender, erect. 

 Fields; June-August; infrequent: reported from Story county. (A. tlibcrosa 

 var. deenmhens Pursh.) 



* *Lcavc* opposite; corolla bright red or purple. 



A. purpurascens L. Purple M. Stem 2-3 feet high, simple, smooth; 

 leaves opposite, short-petioled, ovate or elliptical, short-pointed, short-pubes- 

 cent beneath; umbels solitary, long-peduncled, axillary, pedicels shorter; 

 flowers long, dark purple. Prairies and thickets; June-August; infrequent; 

 Johnson, Henry, Appanoose. Decatur, Ringgold, Union, and Eminet counties; 

 reported from Scott. Muscatine and Story counties. 



A. incarnata L. Swamp M. Stem 2-5 feet high, mostly smooth: leaves 



