UMBELL1FERA E. 68 1 



involucels of numerous narrow bracts. Calyx-teeth minute. Styles short. Fruit 

 ovate or oval, somewhat compressed. Carpels with prominent ribs; oil-tubes 

 1-3 in the intervals. Seed-face flat. [Greek name of a marsh plant.] About 8 

 species, natives of the north temperate zone and South Africa. 



Plant stout, 6-18 dm. high; leaf-segments 7-17, 1. S. cicutaefolium. 



Plant weak, 3-9 dm. high; leaf-segments 3-7. 2. S. Carsoni. 



i. Sium cicutaefolium Gmel. Hemlock Water-parsnip. (I. F. f. 2685.) 

 Erect, stout. Lower leaves long-petioled, the uppermost nearly sessile; leaf-seg- 

 ments linear, or lanceolate, 3-13 cm. long, 3-25 mm. wide, acuminate, sharply 

 serrate; or the lowermost pectinately dissected; umbels 8-20-rayed; rays 1-4 cm. 

 long; fruit ovate, compressed, about 3 mm. long. In swamps, N. S. to Br. Col., 

 Fla., La. and Cal. Very variable in leaf-form. July-Oct. 



2. Sium Carsoni Durand. Carson's Water-parsnip. (I. F. f. 2686.) 

 Stem slender, 3-6 dm. long. Leaf segments 3-7, those of the upper leaves 

 linear, or lanceolate, acute, or acuminate, 2-5 cm. long, 3-6 mm. wide, sharply 

 serrate; lower leaves often floating and very thin, the segments broader and 

 laciniate, or dissected; umbels 7-15 rayed; rays 1-2.5 cm. long in fruit. In 

 streams, Me. to R. I. and Penn. July-Aug. 



28. BERULA Hoffm. 



A glabrous aquatic or marsh perennial, with pinnate leaves, serrate or some- 

 times incised leaf- segments, and terminal compound umbels of white flowers. 

 Involucre and involucels of several narrow bracts. Calyx-teeth very small. Stylo- 

 podium conic; styles short. Fruit subglobose, slightly flattened laterally, glabrous, 

 the ribs very slender, the pericarp thick and corky ; oil-tubes numerous and close 

 together along the inner side of the pericarp. Seed-face flat. [Latin name of the 

 watercress.] A monotypic genus of the north temperate zone. 



I. Berula erecta (Huds.) Coville. Cut-leaved Water-parsnip. (I. F. f. 

 2701.) Erect, rather stout, much branched, 1.5-9 dm. high. Leaflets 7-19, 

 ovate, oval, or linear-oblong, deeply serrate, laciniate, or lobed, I-3.5 cm. long, 

 4-10 mm. wide, those of the upper leaves commonly more laciniate than those 

 of the lower; umbels numerous, short- peduncled, 10-20-rayed; rays 1-6 cm. long 

 in fruit; pedicels 3-6 mm. long; fruit less than 2 mm. long, nearly orbicular, 

 somewhat cordate at the base, the ribs inconspicuous. In swamps and streams, 

 southern Ont. to Br. Col., south to Mass. (?), N. Y., 111., Kans., in the Rocky Mts. 

 to N. Mex. and to Cal. Also in Europe and Asia. July-Sept. 



29. PTILIMNIUM Raf. [DISCOPLEURA DC] 



Annual glabrous herbs, with dissected leaves, and compound umbels of white 

 flowers. Bracts of the involucre filiform or dissected in our species. Calyx-teeth 

 obsolete. Petals obovate, the apex inflexed. Stylopodium conic; fruit ovate, slightly 

 compressed, glabrous. Carpels dorsally compressed, the dorsal and intermediate 

 ribs prominent, slender, the lateral ones thick and corky; oil-tubes solitary in the 

 intervals. Seed-face flat. [Greek, referring to the finely divided leaves.] Besides 

 the following, another occurs in Texas and one in the East Indies. 



Involucral bracts mostly pinnate; fruit 2-3 mm. long. 1. P. capillaceum. 



Involucral bracts short, entire; fruit 1-1.5 mm. long. 2. P. Nuttallii. 



1. Ptilimnium capillaceum (Michx.) Raf. Mock Bisiiop-weed. (I. F. f. 

 2699.) Slender, 3-6 dm. high. Leaves finely dissected into filiform segments; in- 

 volucral bracts or some of them pinnately parted; involucels of several linear 

 bracts; umbels 5-10 cm. broad, 5-20 rayed; fruit ovate, acute. In wet soil, espe- 

 cially brackish meadows, Mass. to Fla., west to Tex. June-Oct. 



2. Ptilimnium Nuttallii (DC.) Britton. Nuttall's Mock Bishop-weed. 

 (I. F. f. 2700.) Similar to the preceding, but generally stouter, 6-9 dm. high, 

 the branches nearly erect. Umbels 7-25-rayed; bracts of the involucre linear, 

 entire, short, those of the involucels minute; fruit ovate-orbicular, obtusish. In 

 i,v/amps, I1L to Kans., La. and Tex. May-Sept. 



