162 



Descriptive Flora 



APOCYNACEAE. Dogbane Family. 



Amsonia temna (A. Gray) Heller. Texas Star. 



Erect plants 1 to 2 feet high, leafy to the top and ter- 

 minating in flat-topped clusters of pale blue flowers. Plants 

 usually branched at the woody root. Leaves simple, narrow, 1 to 

 2" long, crowded along the stems. Corolla tubular, 5-lobed, 

 about y<£ across. Stamens 5, inconspicuous. Pods 2 together, 

 erect, slender, glabrous, 2 to 4 inches long. April and May. On 

 dry limestone hills of the Edwards Plateau. Not common. 

 Named for Amson, an American physician. 



ASCLEPIADACEAE. Milkweed Family. 



Asclepias verticillatu L. Milkweed. 



Tall, slender stemmed plants rarely branched at base and 

 having milky sap and greenish-white clusters of odd flowers 

 about 1 inch across at intervals along the upper part of the 

 simple stems. Leaves narrow, 1 to 2y 2 inches long, opposite, 

 scattered or in whorls of 3 to 6. Flowers irregular, having 5 

 concave hoods. Pods slender, 2y 2 to 4 inches long, splitting on 

 one side and freeing numerous flat, brown seeds, each with a 

 tuft of silky hairs at one end. June to September. In poor, dry 

 soil. 



Asclepias linearis Scheele. Milkweed. 



Similar to the above but usually branched at base and 

 leaves not in whorls. Blossoms in May and June. 



Asclepias texana Heller. Texas Milkweed. 



Smooth, leafy, slender-stemmed plants with milky sap, stems 

 commonly 2 to 3-branched at the fibrous roots, and flowers as in 

 the two preceding species, only whiter. Leaves simple, opposite. 

 Blades thin, oval-oblong, 1 to 2" long. Petioles y 2 to V/ 2 " long. 

 May to July. In rich, shaded ground in the Edward's Plateau 

 Region. Named for Asklepios, the Greek God of medicine. 



