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into wing-like margins of the stem: flowers mostly solitary, terminal and soon extra- 
axillary: corolla white.—Low grounds. 
++ Leaves not decurrent. 
++ Stem leaves all sessile, the upper by a more or less clasping base: villous-pubescent and 
somewhat viscid, 
2. N. undulatum HBK. Erect, diffusely branched, at length procumbent, leafy: 
leaves oblong, the upper with broad sessile base, the lower spatulate: flowers com- 
monly subsessile: corolla somewhat longer than the sepals: pod oblong, more or less 
shorter than the sepals: seeds oval, smooth.—A Mexican species, collected near Bra- 
zos Santiago (Nealley), but mostly represented along the Rio Grande near its mouth 
by var. MACRANTHUM Chois., a looser and less leafy form, with flowers on pedicels (2 
to 10mm, long), corolla almost twice as long, and pod only about half as long as 
sepals, 
3. N. stenocarpum Gray. Like the former, or sometimes with narrower leaves: 
pedicels, ifany, short and rigidin fruit: styles united at base or even higher (occa- 
sionally 3): pod cylindrical, nearly linear (6 mm. long), nearly equaling the partly 
adherent sepals: seeds short, angled, strongly reticulated.—Near the mouth of the 
Rio Grande, westward through Mexico to southern California. 
++ ++ Leaves not at all clasping, more or less tapering at base, at least the lower petioled. 
4, N. hispidum Gray. Hispid or hirsute, repeatedly forked: leaves broadly or 
narrowly linear-spatulate, most of the cauline ones sessile: flowers lateral and soli- 
tary, or 3 to 5 in terminal unilateral clusters: sepals narrowly linear, very little if 
at all broadened upwards: corolla narrow-funnelform, mostly much longer than the 
valyx: pod narrowly oblong, 30 to 40-seeded: seeds smooth.—Plains and prairies 
throughout Texas. 
5. N. dichotomum Ruiz & Pav. Erect, minutely pubescent, glandular: stem 
repeatedly forked and with a nearly sessile flower in each fork: leaves oval or 
oblong-lanceolate: sepals narrowly linear and slightly broadened upwards: corolla 
short-funnelform, hardly exceeding the calyx: pod oblong-oval: seeds coarsely 
pitted.—A Mexican species, collected near Corpus Christi and Roma (Nealley). 
Represented in extreme western Texas by the New Mexican var, ANGUSTIFOLIUM 
Gray, with narrow leaves (linear or nearly so). 
** Perennial, woody-stemmed at least at base. 
+ Flowers solitary in the forks. 
6. N. origanifolium HBK. Herbaceous from a woody base, or suffruticulose, 
low and small: leaves oblong or spatulate-obovate, sessile by a narrowed base or 
short-petioled, soft-pubescent: flowers short-peduncled: corolla 6 mim. long, sur- 
passing the calyx: seeds about 20, oblong, smooth.—Crevices of rocks, near the Rio 
Grande, from Roma (Nealley) to the Limpia and Guadalupe Mountains, and adjacent 
Mexico, 
+ + Flowers cymulose : corolla 8 to 10 mm. long, salverform. 
7 N.Havardi Gray. Herbaceous from a woody base, 3 dm. or more high, more 
or less cinereous with soft pubescence: stem erect and stout: leaves oblong or upper- 
most lanceolate: tlowers short-pediceled: filaments membranaceous-margined, 
toothless: seeds 16 or more, globular or short oval.—Southwestern borders of Texas, 
on alkaline bank of Tornillo Creek (Harard), 
8 N. stenophyllum Gray. Sutiruticose, 3 dm. high or less, rather stout, 
strigulose-cinereous or more loosely hirsute: stems very leafy throughout: leaves 
from narrowly linear to almost filiform: flowers densely cymulose at summit of 
branches: margin of filaments on each side terminating above in a free short tooth: 
seeds about 40, globular and angulate.—Southern and western borders of Texas, 
