212 AMMIACEAE. 



umbels long-peduncled ; rays 2-4 cm. long: petals white, obovate or orbicular- 

 obovate, 1-1.5 mm. long: fruits conic-ovoid, about 4 mm. long. — M. Occa- 

 sional, on roadsides and in thickets near Lancaster. Nat. of Eu. — Sum. — 



GOUTWEED. 



15. SIUM [Tourn.] L. Perennial herbs. Leaf -blades pinnately com- 

 pound. Umbels compound. Involucres and involucels of narrow bracts and 

 bractlets. Sepals small, acute. Petals white. Fruit stout, somewhat laterally 

 flattened: carpels ribbed, the intervals with 1-3 oil-tubes. Seeds 5-angled. 



1. S. cicutaefolium Schrank. Plants 5-18 dm. tall: leaflets 7-17, linear, 

 oblong, or lanceolate, 4-15 cm. long, sharply serrate (submersed leaves some- 

 times finely dissected) : fruits orbicular to oblong-orbicular, 3-3.5 mm. long. 

 — Frequent, in the Susquehanna valley. • — Sum. — Water-pabsnip. 



16. LIGUSTICUM L. Perennial herbs with large roots. Leaf-blades 

 ternately compound. Umbels compound. Involucres of a few narrow bracts. 

 Involucels of numerous narrow bractlets. Sepals obsolete. Petals white, 

 broadened upward. Fruit more or less elongate: carpels with sharp prominent 

 ribs and 2-6 oil-tubes in each interval. 



1. L. canadense (L.) Britton. Stems 5-20 dm. tall: leaflets oblong, elliptic- 

 oval, or ovate, 3-8 cm. long, coarsely toothed: fruits oblong, oval, or ovate, 4-6 

 mm. long, the ribs narrow-winged. — S. Eare, in rich woods. — Schists. — 

 Sum. — Angelico. Nondo. 



17. THASPIUM Nutt. Perennial herbs. Leaf-blades 3-foliolate or ter- 

 nately compound, or those of the basal leaves sometimes simple. Umbels 

 compound. Involucre of few bracts. Involucels of many bracts. Sepals 

 present. Petals yellow or purple. Fruit longer than wide: carpels with 

 winged ribs and 2-6 oil-tubes in each interval. — Sum. — Meadow-parsnip. 



Petal-blades less than 1 mm. long : leaves with ternate blades : leaflets relatively 



thick, crenate. 1. T. trifoUatum. 



Petal-blades over 1 mm. long : leaves with biternate blades : 



leaflets relatively thin, incised or lobed. 2. T. iarhinode. 



1. T. trifoUatum (L.) A. Gray. Stems 2-7 dm. tall: leaf -segments ovate to 

 lanceolate, serrate: corolla dark-purple (or deep-yellow in T. trifoUatum 

 aureum) : fruits globose-ovoid, about 4 mm. long. — - M. Eare, in the Dillerville 

 swamp, Lancaster. — Limestones. 



2. T. barbinode (Miehx.) Nutt. Stems 3-12 dm. tall: leaf -segments commonly 

 ovate, coarsely toothed, cleft, or parted: corolla pale- or light-yellow: fruits 

 oblong or oval, 5-6 mm. long, glabrous. — Common, in moist places. 



18. ANGELICA L. Perennial caulescent herbs. Leaf -blades pinnate or 

 decompound. Umbels compound. Involucres and involucels present or want- 

 ing. Sepals small or obsolete. Petals white or greenish, broadest above the 

 middle. Fruit longer than broad: carpels wath the dorsal and contiguous 

 ribs prominent, and broadly winged lateral ribs: oil-tubes solitary or several 

 in the intervals and 2-10, or more, in the inner face. — Sum. and fall. — 

 Angelica. 



Fruit glabrous : branches of the umbel glabrous or nearly so : leaves with acute 

 or acutish segments. 1. A. atropurpurea. 



Fruit pubescent : branches of the umbel copiously pubescent : 



leaves with obtuse segments 2. A. villosa. 



1. A. atropurpurea L. Plant 11-21 dm. tall, the stem dark-purple: leaflets 

 2.5-7.5 cm. long; blades thick, ovate to lanceolate, coarsely serrate: umbel- 



