AMMIACEAE 
Corolla white: stylopodium conic (except in Angelica). 
Oil-tubes morc than one in the intervals. 
es 2-3 pinnately decompound, the segments 
na ions 38. CONIOSELINUM. 
Leaf-blades 1-2 ternately divided, the segments 
b 39. ANGELICA. 
Oil-tubes solitary in the inter 
Fruit notched at the apex, M carpels very flat. 40. HERACLEUM. 
Fruit not notched at the apex, the carpels not very 
flat. 41. OXYPOLIS. 
1. ERYNGIUM Tourn. L. Biennial or perennial herbs. Leaf-blades 
spiny-toothed, lobed o r incised, or rarely entire. Bracts of the involucre often 
ing the leaves. Sepals acute or spine-like. 
Gos. BUTTON-SNAKEROOTS.— Some species are accredited 
with medicinal paneer 
Leaf-blades parallel-veined. I. AQUATICA, 
Leaf-blades not pa arallel veined. 
ades of the b asal- leaves lobed or parted, the segments 
spine-tipped. 
Heads Sa as spiny-bristly: bracts and bractlets 
3—5-pronged. II. AROMATICA. 
Heads ovoid to K not bristly: bracts and bract- 
lets not 3-pronged. III. DIVARICATA. 
Blades i the basal leaves entire or merely toothed. 
Stem and ae es filiform or very slender, prostrate: 
Dla nts bi IV. PROSTRATA. 
Stem relatively stout, erect or ascending: plants peren- 
nial, or, perhaps rarely biennial. V. INTEGRIFOLIA. 
I. A A 
Petals ovate, acuminate: bristles on the leaf-margin solitary. 1. E. aquaticum. 
un Dod ee mucronate: bristles on the leaf-margin 
r 2-4 together. 2. E. synchaetum. 
II. AROMAT 
Diffuse plant, the br anches from the top of uie r 
iu inflorescence near the tip of the branches widely 
anched. 3. E. aromaticum. 
Plant erect, the stem corymbosely branched at the top: leaf- 
blades with 3-5 apical prong-like teeth. 3a. E. cuneifolium. 
IIL DIVARICA | 
Prostrate plant, the heads mostly axillary, di — than 
wide. 4. E. divaricatum. 
a ATA 
Bractlets longer than the flowers: s with narrow 
blades or segments: fruit strongly “tubereulate b. E. Baldwinii. 
Bractlets shorter than the flow m-leaves I broad 
blades or segments: fruit Bot. Pe tuberculate. 6. E. prostratum. 
VY. INTEGRIFOLIA 
Lower leaves with elongated hollow petioles and long blades. 
Bractlets entire. T. E. floridanum. 
Bractlets 3- Done ed. 
s us the bractlets unequal, the lateral teeth 
8. E. virginianum. 
Tee f the bractlets about equal. 9. E. Ravenelii. 
Lower us with short petioles and bI lades 
Leaf-blades ovate, iun 5 e or CE serrate or cre- 
nate: heads mostly r 7 mm. high. 10. E. integrifolium. 
Leaf-blades linear or eoa e laciniately toothed, 
at least near the base: heads mostly less than 7 mm. 
high. 11. E. ludovicianum. 
1. E. aquaticum L. Plant 3—18 dm. tall: blades of the lower inis broadly 
linear, mostly 2-9 dm. long, stiff: sepals ovate to elliptie-ovate, about 2.5 mm. 
