50 NYCTAGINE^:. 



nate: perianth shortly cleft; outer segments broadly ovate, erose, retuse 

 or emarginate, the inner narrow and lacerate: stamens 3; anthers orbic- 

 ular. Wooded hills of Sonoma and Lake counties. June Sept. 



7. PTEROSTEGIA, Fisch. & Mey. Our species diffusely dichoto- 

 mous slender and flaccid (or in age somewhat wiry) annual with oppo- 

 site, petiolate, exstipulate 2-lobed leaves, and small foliaceous bracts. 

 Involucres each of a single bract shorter than the solitary sessile flower, 

 rounded and 2-lobed, in age larger, reticulated, loosely enfolding the 

 achene, and gibbously 2-saccate on the back. Perianth 5- or 6-parted; 

 segments equal, oblong-lanceolate. Stamens as many or fewer, inserted 

 at the base of the segments. Achene triquetrous. 



1. P. drymarioides, Fisch. & Mey. Glabrous or hirsute-pubescent: 

 leaves obovate, obcordate or reniform-bifid, often with the lobes again 

 2-lobed, the lowest petiolate, the upper sessile, % % in. long: fl. minute : 

 fructiferous involucre 1^ lines long, closely enfolding the minute light 

 brown achene. Common on rocky hills, and sandy banks. June. 



ORDER XVI. NYCTAO'lNE/E. 



Herbs or suffrutescent plants (ours mostly coarse and fleshy seaside 

 herbs) with tumid joints, opposite exstipulate entire leaves and showy 

 perfect flowers in axillary pedunculate and involucrate clusters. Invo- 

 lucre calyx-like, closely subtending the flower-cluster. Perianth corolla- 

 like, campanulate, salverform or tubular, the persistent base indurated 

 and constricted over the 1-celled 1-seeded free ovary. Stamens few, 

 hypogynous; filaments slender; anthers small and rounded. Pistil 1, 

 simple. Seed erect; embryo encircling a copious mealy albumen. 



1. ABROMA, Juss. Viscid-pubescent rather succulent herbs with 

 opposite and somewhat unequal leaves. Flowers in umbel-like heads on 

 rather long axillary peduncles. Involucre of 515 distinct or slightly 

 united somewhat scarious bracts enfolding the base of the heads. Peri- 

 anth salverform; limb of 5 or 4 emarginate or obcordate lobes. Stamens 

 mostly 5, adnate to the tube and not exserted. Stigma linear-clavate. 

 Fruit coriaceous. 3 5-winged, enclosing a smooth cylindric achene. 

 Embryo with but one cotyledon. 



* Wings thin but solid; body of fruit rigid or ligneous. 



1. A. umbellata, Lam. Perennial, prostrate, rather slender, viscid- 

 puberulent, the stems 1 3 ft. long: leaves almost glabrous, ovate to 

 narrowly oblong, 1 1^ in. long, narrowed to a slender petiole, obtuse, 

 the margin often somewhat sinuate: peduncles 2 6 in. long: bracts of 

 the involucre narrowly lanceolate, % in. long; head 10 15 flowered: 



