ASCLEPIADACEAE (MiLKWBEli FAMILY) 387 



with small auricles at base much involute and concealed, alternated by as 

 many short and roundish or gland-like, small internal teeth: anthet- wings 

 semi-rhomboid above, with a, much longer tapering; base. — Froih Colorado to 

 the Saskatchewan kna eastward across the continent. 



2o. Acerates viridiflora Ivesia Brit. Mem. Torr. Club 5: 265. 1894. Leaves 

 lanceolate or oblong-lanceolate,, 5^12 cm. long. — Same range and oiften with 

 the species. 



26. Acerates viridiflora linearis Gray, Syii: Fl. 2: 90.' 1878. Leaves 

 elongated-linear, stems low, and umbels usually solitary.— New Mexico to' 

 Canada. 



3. Acerates angustifolia (Nutt.) Dec. in DC. Prodr. 8: 522. 1844. Stein 

 puberulent but foliage glabrous, slender, 3-5 dm. high, simple: leaVes long 

 and narrowly linear, with sca,b[rous and more or less revolute margins and a 

 strong midrib; the upper alternate and the lower opposite: umbels several, 

 ip-15-flowered; flowers greenish: hoods whitish, erect, equaling the anthers, 

 coiidiiplicate-«qncave, the base of each inner margin appendaged by a cuneate, 

 erosely truncate lobe, the apex 2-lobed' and the narrow internal crest exserted 

 in the sinus in the form' of an intermediate tooth; interior crown of 5 very 

 small 2-l6bed processes between the bases of the anthers: follicles long- 

 acuminate, erect On the ascending pedicel. Acerates steriophylla Decaisne. — 

 Prom Colorado and Nebraska to Texas. 



2. ASCLEPIAS L. Milkwebd 



Herbs with erect or merely spreading stems, opposite or sometimes verticil- 

 late or alternate jleayes, and terminal and lateral umbellate inflorescence. 

 Calyx 5-parted, comimonly bearing some minute processes at the base within., 

 CflroUa ,, rotate,, 5-parted, dextrorsely valyate-convolute in the bud; crown 

 consisting of 5 distinct cucullate or hpllowed, nectariferous appendages, op- 

 posite the anthers^ that are inyolute or complicate and beiaiing a porn or crest- 

 like process from the back or toward the base within, either sessile or elevated 

 on a col,umn which is, shorter than the anthers. Anthers tipped with an in- 

 flexed or, sonietimes erect membrane; the ppUiniferous cells lower than the 

 stignia; poUen masses suspended, attached in pairs to the glands of the 

 stigmatic ring. 



Corx>Ila and cro\7Q orange or bright red. 



Leavea nearljr all akematfe; corolla orange . . . , 1. A. tuberosa. 



Leaves opposite; corolla red : . 2. A. incamata. 



Corolla greenish, purplish, yellowish, or white. , . 



Leaves lanceolate or broader (not linear). 



Leaves sessile, verjr broad (suborbicular), soon glabrous. r 



I Horns concealed; leaves obtuse . . ... 3. A. crjrptoceras; 



Horns exserted; leaves retuse ^ . . . 4. A. latiiolia. 



Leaves petioled, lanceolate.or broader, canescent or tomen- 



tdse, or in No. 7 nearlj; glabrous. ' ■ ' 



Leaves' obtuse; ^follicle' with soft spinose processes . ^ . 5. A. speciosa^; -, ., . ,. . 

 ' I . Leaves lanceolate or obovate; follicle. )vithout spinose- i 



processes. , ' , 



L^ves obovate-retuse, densely tomentose-canescent . 6. A. arenaria. 



Leaves lanceolate, glabrate ' 7. A. Hallii. . > 



Leaves linear. i.,, ,,,',,.., ' ,; , 



Leaves opposite . < . . . . . , . . . 8. A. brachystephaha. 



Leaves verticillate or Scattered. ' ' ' 



' '. ' ' 'Plant tall; 4^6 dm. high; leaves verticillate. 

 ■ ,'i :a Hoods entire . .... . . . . 9. A. v^rticillata 



( ,; Hoods dbrga|lly hastate-sagittate , . . . . 10. A.' galioides. 



Plant low,' !£ -2 dm. high; leaves crowded, filiform-linear . 11. A. pumila.' 



1. Ascleipias tuberosa L. Sp. PI. 217. 1753. Hirsute or roughish-pubescent, 

 4-8 dm. nigh, very leafy to the top: leaves lanceolate-oblong to linear- 

 lanceolate, sessile or slightly petioled: umbels several and mostly cymose at 

 the summit of the stem: hoods narrowly oblong, erect, deep bright orange,- 

 much suipassing the anthers, almost as long as the purphshr or slightly 

 greenish-orange, oblong corolla-lobes, nearly equaled by the filiform-subulate 



