610 UMBELLIFERiE. Sium. 



terete. — Aquatic perennial glabrous (poisonous) herbs, with terete fistulous 

 stems. Leaves 3-pinnately or 3-ternately divided. Involucre few-leaved 

 or none. Involucels many-leaved. Flowers white. 



1. C. virosa (Linn.) : trunk of the root and lower part of the stem hollow 

 and divided by transverse partitions ; leaves tripinnately divided ; segments 

 lanceolate, serrate ; umbels opposite the leaves and terminal. DC. — Linn, 

 spec. 1. p. 255 ,• Engl. hot. t. 1191 ; DC.prodr.4. p. 99 ; Hoolc. fl. Bor.- 

 Am. l.p. 259. 



Woody country, British America, between lat. 54° and 64°, Dr. Richard- 

 son, Drunwiond. — We have no North American specimens. Like the fol- 

 lowing species, it is exceedingly poisonous. 



.- 2. C. maculata (Linn.) : root with thick oblong fleshy fibres ; stem 

 streaked with purple ; leaves biternately divided ; segments lanceolate, mu- 

 cronatelv serrate ; uinbels terminal and axillary. — Linn.! I.e.; Pursh, Ji. 

 1. p. 195 ; Ell. sk. l.p. 357 ; Bigd.lfl. Bost. ed. 2. p. 115, S^-med. hot. 1. 

 t. 12; Torr.! fl.l. |>. 308. 



Swamps, Canada ! to Georgia ! and Louisiana ! West to Oregon. July- 

 Aug. — Stem 4-8 feet high, finely striate with green and purple, and some- 

 times spotted (in the shade often wholly green). Lower leaves on long 

 petioles ; the terminal division quinate or pinnate ; segments more or less 

 broadly lanceolate, all of them petiolulate, the primary veins running to the 

 notches (instead of the ptoints) of the serratures (as first noticed by Dr. 

 Darlington). Rays of the umber long and slender. Involucre usually 

 none, or of 1-2 small leaflets. Involucels of 5-6 short linear leaves. Fruit 

 about a line and a half in diameter, aromatic and somewhat resembling 

 anise. Ribs broad, filled with a white cellular substance ; the lateral ones 

 much broader than the others. — Water Hemlock. Spotted Cowbane. Beaver 

 Poison. Musquash. — The root is highly poisonous to men and cattle: the 

 herb also is said to be poisonous. 



f" 3. C. hulhifera (Linn.) : root with thick oblong fleshy fibres ; axils of the 

 branches bulbiferous ; leaves biternately divided ; segments linear and linear- 

 lanceolate, remotely toothed ; umbels terminal and axillary. — Linn. ! spec. 

 1. p. 255 ; Michx. .' Ji. I. p- 165 ; Nult. gen. I. p. 192 ; DC. .' prodr. 

 4. p. 99. 



Swamps, Canada ! to Pennsylvania ! August. — Stem 2-4 feet high, 

 slender; the axils of the branches bearing small verticillate bulbs. Leaves 

 usually very finely divided (especially in the infertile stems), with linear 

 segments scarcely a line wide. Umbel with rather short slender rays. Fruit 

 (according to Nuttall) scarcely distinguishable from that of the preceding 

 species. — A somewhat rare plant, often sterile, and sometimes also without 

 bulbs. 



12. SIUM. Linn, (partly) ; Koch, Umb. p. 117; DC. prodr. 4. p. 124. 



Margin of the calyx 5-toothed or obsolete. Petals obovate, emarginate, 

 with an inflexed point. Fruit ovate, or subglobose and compressed at the 

 sides, or contracted and somewhat didymous, crowned with the depressed 

 stylopodium and recurved styles. Carpels with 5 rather obtuse ribs. Inter- 

 vals usually with several vittae. Carpophore 2-parted. Seed somewhat 

 terete. — Perennial mostly aquatic herbs. Leaves pinnately divided ; the 

 segments usually ovate or lanceolate, toothed or serrate : submerged leaves 

 aivided into numerous capillary segments. Umbel many-rayed. Umbellets 



