-t 



ASCLKIMADACEAE. 



Vol. J 11. 



bases to the filaments, introrsely 2-celled, connivent around the stigma, or more 

 or less united with each other ; anther-sacs tipped with an inflexed or erect scarious 

 membrane, or unappendaged at the to;), sometimes appendaged at the base; pollen 

 coherent into waxy or granular masses, one or rarely two such masses in each sac, 

 connected with the stigma in pairs or fours, by 5 glandular corpuscles alternate with 

 the anthers. Disk none. Ovary of 2 carpels; styles 2, short, connected at the 

 summit by the peltate discoid stigma ; ovules numerous in each carpel, mostly 

 anatropous, pendulous. Fruit of 2 several-many-seeded follicles. Seeds com- 

 pressed, usually appendaged by a long coma ; endosperm cartilaginous, mostly 

 thin; embryo nearly as long as the seed; cotyledons flat. 



About 220 genera and 2000 species, of very wide geographic distribution, most abundant in 

 tropical or warm-temperate regions. 

 Erect or decumbent herbs. 



Corona-hoods each with an incurved horn within ; eaves mostly opposite. 



Corona-hoods prominently crested within ; leaves alternate. 



Corona-hoods unappendaged or with a thickened crest-like keel. 

 Twining vines. 



Corolla-lobes erect ; corona-lobes 1-2-awned. 



Corolla rotate. 



Anthers tipped with a scarious membrane ; pollen-masses pendulous. 



A it 1.. i.* J . 11 1 _ ._1 



Anthers merely tipped; pollen-masses horizontal. 



1. Asclepias. 



2. Asclepiodora. 



3. Accrates. 



4. Gonolobus. 



5. Cynanchum. 



6. Vincetoxicum. 



i. ASCLEPIAS L. Sp. PI. 214. 1753. 

 Perennial erect or decumbent herbs, with opposite verticillate or rarely alternate entire 

 leaves, and middle-sized or small flowers in terminal or axillary umbels. Calyx 5-parted or 

 5-divided, usually small, the segments or sepals acute, often glandular within. Corolla deeply 

 5-parted, the segments mostly valvate, reflexed in anthesis. Corona-column generally present. 

 Corona of 5 concave erect or spreading hoods, each bearing within a slender or subulate 

 incurved horn, either included or exserted. Filaments connate into a tube ; anthers tipped 

 with an inflexed membrane, winged, the wings broadened below the middle ; pollen-masses 

 solitary in each sac, pendulous on their caudicles. Stigma nearly flat, 5-angled or 5-lobed. 

 Follicles acuminate. Seeeds comose in all but one species. [Dedicated to Aesculapius.] 



About 95 species, mostly natives of the New World ; besides the following, some 25 others occur 

 in southern and western North America. Known as Milkweed, Silkweed, or Swallow-wort. Type 

 species : Asclepias syrlaca L. 



* Corolla and corona orange; leaves alternate or opposite. 

 Stem erect or ascending; leaves nearly all alternate. 1. A. tuberose 



Stems reclining; leaves, at least the upper, opposite, oblong or oval. 2. A. decumbens. 



**Coiolla bright red or purple (sometimes greenish in A. rubra) leaves opposite. 

 Flowers 4"-6" broad ; corona-hoods 2" 3" high. 



Leaves lanceolate or linear ; hoods oblong, obtuse. 

 Leaves ovate or ovate-lanceolate ; hoods lanceolate. 

 Leaves oblong, ovate or ovate-oblong ; hoods oblong, acutish. 

 Flowers 2" -3" broad ; corona-hoods i"-i}4" high. 



Plant nearly or quite glabrous ; leaves lanceolate or oblong-lanceolate. 

 Plant pubescent ; leaves oblong. 



*** Corolla greenish, purplish, yellowish or white; leaves opposite or verticillate. 

 Leaves ovate, oblong, ovate-lanceolate, obovate or orbicular. 

 Plants glabrous throughout, or minutely pubescent above. 

 Leaves sessile, clasping or very short-petioled. 



Peduncles of the solitary or several umbels short. 



Leaves ovate-oblong ; hoods 2-auriculate at the base. 

 Leaves nearly orbicular ; hoods truncate. 

 Peduncle of the usually solitary umbel elongated. 

 Leaves wavy-margined. 

 Leaves cordate-clasping. 

 Leaves rounded at the base, short-petioled. 

 Leaves sessile, flat ; horn not exceeding the hood. 

 Leaves manifestly petioled. 



Corolla greenish ; umbels loose, the pedicels drooping. 

 Corolla white ; umbels dense. 



Corolla pink ; some of the leaves verticillate in 4's. 

 Plants, at least the lower surfaces of the leaves, canescent or tomentose. 

 Follicles tomentose, covered with soft spinose processes. 

 Corona-hoods obtuse, short. 

 Corona-hoods elongated, lanceolate. 

 Follicles with no spinose processes, glabrous or pubescent. 

 Leaves wavy-margined ; corolla-segments a,"-$" long. 

 Leaves flat ; corolla-segments 2"$" long. 

 Leaves lanceolate, oblong-lanceolate or linear. 



Leaves opposite, lanceolate or oblong-lanceolate. 



Leaves thick, short-petioled; inflorescence woolly. 

 Leaves thin, slender-petioled ; inflorescence downy. 



3. A. lanceolata. 



4. A. rubra. 



5. A. purpurascens. 



6. A. xncarnata. 



7. A. pulchra. 



A. Sullivantii. 



A. latifolia. 



A. amplexicautis. 

 A. intermedia. 

 A. Meadii. 



A. cxaltata. 

 A.variegata. 

 A. quadrifolia. 



16. A. syriaca. 



17. A.speciosa. 



19. 



A.arenaria. 

 A. ovalifolia. 



20. A.brachystephana, 

 2\. A. perennis. 



