874 AMMIACEAE 
36. PHELLOPTERUS Nutt. 
Perennial acaulescent or nearly acaulescent herbs, with thick roots. Leaves basal : 
blades bipinnate. Flowers inconspicuous. Involucres rarely present. Involucels of hyaline 
bractlets. Sepals manifest. Petals pink, purple or rarely white, inflexed at the apex. Disk 
flat, stylopodium wanting. Fruit oblong to orbicular, slightly dorsally flattened : carpels 
with 3-5 wings of about equal breadth : oil-tubes usually 3 in the intervals. Seeds flattened. 
Corolla white: bractlets of the involucel entire: fruit 8-12 mm. long. 1. P. montanus. 
Corolla pink: bractlets of the involucel fringed: fruit 4 mm. long. 2. P. macrorhizus. 
1. Phellopterus montanus Nutt. Roots elongated, sometimes fusiform. Foliage 
often pubescent when young. Leaves clustered ; blades glaucous, bipinnately parted or 
bipinnate, 4-10 cm. long, the segments pinnatifid, suggesting pinnae of many common 
species of ferns: peduncles very short, solitary or clustered, the umbels during anthesis 
appearing sessile in the cluster of leaves: rays 6-12, unequal, 6-18 mm. long: bracts of 
the involucre and involucels conspicuous, membranous, entire: fruit oblong in outline, 
8-12 mm. long: wings of the carpels 3-5, very thin, from a thicker ‘base ; oil-tubes 1-3 in 
the intervals, and 4-8 on the commissural side. 
On dry slopes or hillsides, Wyoming to Nebraska and Texas. Spring. 
2. Phellopterus macrorhizus (Buckl.) Coult. & Rose. Similar to P. montanus in 
habit, but with peduncles becoming twice as long as the leaves: umbels with longer rays 
and pedicels: bractlets of the involucels lacerate at the apex: corolla pink: fruit 4 mm. long. 
On prairies, eastern Texas. Spring and summer. 
| 37. CYMÓPTERUS Raf. 
Perennial dwarf acaulescent herbs. Leaves alternate, basal: blades pinnate or bipin- 
nate. Involucre generally wanting. Involucel of foliaceous bractlets. Umbels dense. 
Hypanthium truncate or supporting small sepals. Corolla white or yellow. Stylopodium 
wanting. Fruit dorsally flattened, broad, normally glabrous: carpels with the dorsal and 
intermediate ribs filiform or winged, the lateral wings broad, corky, those of each carpel 
coherent until maturity : oil-tubes small, 4-8 in each interval, and 8-14 on the commissural 
side. Seeds flat. 
1. Cymopteris acaülis (Pursh) Rydb. Plant glabrous, 7-20 cm. tall. Peduncles 
clustered, mostly surpassed by the leaves: umbels congested: bractlets linear, entire: 
corolla white : fruit oval, 6-8 mm. long, each carpel with 3-5 broad wings. 
On dry plains, Assiniboia to Arkansas and Colorado. Spring. 
38. POLYTAENIA DC. 
Perennial caulescent herbs, with thick roots. Leaves alternate: blades pinnately 
decompound. Flowers in compound umbels. Involucres and involucels of few narrow 
bracts or the former wanting. Sepals triangular. Petals broadest above the middle, 1n- 
flexed at the apex. Disk without a stylopodium. Fruit strongly flattened dorsally : oue 
pels with the dorsal and contiguous ribs corky but obscure and thick broadly winged lateral 
ribs with a nerve near the margin : oil-tubes numerous, 12-18 accompanied by smaller ones 
irregularly disposed. 
1. Polytaenia Nuttállii DC. Root fusiform. Foliage nearly glabrous: stems i 
dm. tall, often branching above, slightly scabrous : leaf-blades twice pinnately divide EE 
parted, 5-20 cm. long, the lower ones long-petioled, the upper nearly sessile ; segments nar 
rowly cuneate, toothed or lobed: umbels peduncled, 2-7 cm. broad: bracts of the in 
volucres wanting : rays 6-12, 2-3 cm. long, a few conspicuously short: pedicels 2-4 Eve 
long : corolla 2.5-3 mm. broad : fruit broadly oblong, 6-10 mm: long, the edges thickened, 
the faces often depressed. Coult. & 
Ind il, Michi to Wi In; P dT . Spring.—P. Nuttallii Tezàna Cours, 
Rose, has obovate fruit with thinner wings, filiform dorsal and | intermediate ribs and broader more 
tinct oil-tubes ; it occurs in southern Texas. 
39. OXYPOLIS Raf. 
Perennial caulescent herbs of marshy localities, with glabrous foliage. Leaves re 2 
nate: blades pinnate or ternate, or rarely reduced to hollow septate phyllodes : lea #0 
toothed. Flowers perfect, in compound umbels. Sepals acute. Petals white. Disk wi 
