870 AMMIACEAE 



pound umbels. Involucres and involucels of narrow bracts. Sepals small, acute. Petals 

 white, inflexed at the apex. Disk with a conic or rounded stylopodium. Styles short. 

 Fruit stout, somewhat laterally flattened : carpels ribbed, the intervals with 1-3 oil-tubes. 

 Seeds 5-angled. Water Parsnip. 



1. Slum cicutaefolium J. F. Gmel. Stems 5-18 dm. tall, more or less branched : 

 leaf-blades 1-8 dm. long, pinnately compound ; leaflets 7-17, linear, oblong or lanceolate, 

 4-15 cm. long, acute, sharply serrate ; submersed leaf-blades sometimes finely dissected : 

 umbels peduncled, many-rayed, 3-10 cm. broad ; rays 2.5-4 cm. long : corolla white, 

 about 2 mm. broad : fruit orbicular or oblong-orbicular, 3-3.5 mm. long, prominently 

 ribbed, with 2-6 oil-tubes on the commissural sides. [<S'. lineare Michx.] 



In low grounds or shallow water, Nova Scotia and Newfoundland to British Columbia, Florida, 

 Louisiana and California. Summer and fall. 



26. BERULA Hoffm. 



Perennial more or less aquatic caulescent herbs. Leaves alternate : blades pinnate, 

 the segments variously cleft. Involucres and involucels present. Flowers in many-rayed 

 umbels. Hypanthium supporting minute sepals. Corolla white. Stylopodium conic. 

 Fruit laterally flattened, about as broad as long, notched at the base : carpels turgid, with 

 slender inconspicuous ribs and a corky pericarp : oil-tubes several, contiguous around the 

 seed cavity. Seeds nearly terete. 



1. Berula er6cta (Huds. ) Coville. Stems 1.5-9 dm. tall, sometimes lower.^ leaves 

 glabrous, the segments 10-18, linear to oblong or even ovate, 1-7.5 cm. long, mostly ser- 

 rate, incised or laciniately lobed : umbels many-rayed, the rays 5 cm. long or shorter : fruit 

 suborbicular or orbicular-ovoid, nearly 2 mm. long, scarcely ribbed. 



In swamps and streams, Ontario to British Columbia, Texas, Mexico and California. Spring to fall. 



27. PTILIMNIUM Raf. 

 Annual caulescent herbs. Leaves alternate : blades pinnately or ternately dissected 

 into narrow or filiform segments. Flowers in compound umbels. Involucres and involu- 

 cels of several slender often dissected bracts. Hypanthium truncate. Petals white, 

 broadened upward. Disk with a thick stylopodium. Fruit slightly flattened, smooth : 

 carpels wide, the dorsal and contiguous ribs prominent, the lateral ones thick and corky, 

 between each of which is an oil-tube. Seed angled. {_Discopleura DC. ] Bishop-weed. 



Fruit subglobose or ovoid, 1-2 mm. long : leaf-segments less than 1 mm. broad, entire. 



Bracts of the involucre pinnate : fruit barely 2 mm. long. 1. P. capillaceum. 



Bracts of the involucre entire : fruit fully 2 mm. long. 2. P. Nuttallii. 



Fruit oblong, 3-4 mm. long : leaf-segments over 2 mm. broad, laciniate- toothed. 3. P. laciniatum. 



1. Ptilimnium capillaceum (Michx.) Hollick. Stems slender, erect or decumbent, 

 2-18 dm. tall, more or less branched : leaf-blades finely dissected ; segments filiform : bracts 

 of the involucres filiform, cleft or parted : umbels peduncled, 2-6 cm. broad: rays 5-20, 

 8-25 mm. long, rather uniform in length : pedicels 3-6 mm. long, filiform : corolla white, 

 about 1 mm. broad : fruit broadly ovoid, barely 2 mm. long, pinched under the apex, 

 prominently ribbed. 



In wet sandy soil, often in brackish meadows, Massachusetts to Florida and Texas. Spring to fall. 



2. Ptilimnium Nuttdllii (DC.) Britton. Stems erect or ascending, stouter than 

 those of the preceding species, 4-10 dm. tall, branching above : leaf-blades dissected like 

 those of R. capilkicum, but rather firmer : bracts of the involucres linear, mostly entire : 

 umbels larger than those of the preceding species : rays 7-25, becoming stout, ascending : 

 corolla white, about 2 mm. broad : fruit oval or globose-oval, fully 2 mm. long, not 

 pinched under the apex. 



In swamps and on damp hillsides, Illinois and Arkansas to Georgia and Texas. Spring to fall. 



3. Ptilimnium laciniktum (Engelm. & Gray) Kuntze. Stems erect, 5-10 dm. tall, 

 branching above : leaf-blades coarsely dissected ; segments linear or lanceolate, acute or 

 acuminate, laciniately pinnatifid or toothed : umbels peduncled, 4-8 cm. broad : rays 8-18, 

 1.5-3 cm. long, nearly equal in length: bracts of the involucres 3-5-parted, with slender 

 segments: bractlets similar but smaller: corolla white, 3-3.5 mm. broad: fruit oblong, 

 3--4 mm. long, the dorsal ribs flat, the lateral forming a prominent acute margin. 



On prairies, Texas. Spring and summer. 



