ZIZIA. LXVII. UMBELLIFERJE. 287 



to Can. Stem 3 if high, round, striate, hollow, green, branching. Leaves 

 various, those of the stem generally biternate, of the branches ternate. Leaf- 

 lets or segments 2 4' long, 1 4" wide, linear or lance-linear, smooth, with 

 slender teeth. Bulblets often numerous, opposite, and within the axils of the 

 bracteate petioles. Umbels terminal. Involucre 0. Umbellets of close, small, 

 white flowers, and slight involucels. Aug. 



8. SIUM. 



Celtic siio, water ; that is, a genus of aquatic plants. 



Calyx margin 5-toothed or obsolete ; petals obcordate, with an in- 

 flexed point ; fruit nearly oval ; carpels with 5 obtusish ribs, and 

 several vittee in each interval; carpophore 2-parted. % Aquatic. 

 Lvs. pinnately divided. Umbels perfect, with partial and general many- 

 leaved involucra. Fls. white. 



1. S. LATIFOLIUM. Water Parsnep. 



St. angular, sulcate ; Ifls. oblong-lanceolate, acutely serrate, acuminate ; 

 col. teeth elongated. A tall plant in swamps and ditches, N. J. to la. ! and Can. 

 Stem about 3f high, smooth, hollow, with 7 deep-furrowed and prominent an- 

 gles. Leaflets or segments 4 6' long, 12' broad, equally serrate, in about 4 

 pairs, with an odd one, those submerged, if any, pinnatifid. Petioles embrac- 

 ing the stem. Umbels large, with many-flowered rays. Flowers small, white. 

 Jl. Aug. 



2. S. LINEARE. Michx. (S. latifolium, /?. lineare. Bw.) 



St. angular, sulcate ; Ifts. 9 11, linear and lance-linear, finely serrate, 

 acute ; col teeth obsolete. More common than the last, in swamps, N. J. to 

 la. ! and Can. Stem 2 4f high, smooth, with 7 prominent angles. Leaflets 

 24' long, 2 4" (rarely 10") wide, the odd and lower ones petiolulate, middle 

 pairs sessile. Umbels 1J 2 7 broad. Involucre of 5 or 6 linear bracts, J as 

 long as the 15 21 rays. Umbellets with numerous, small, white flowers. 

 Fruit roundish, crowned with the broad, yellowish stylopodium. Jl. Aug. 



9. CRYPTOT^ENIA. DC. 



Gr. icpviTTto, to conceal, raivta, a wreath or border; from the obsolete border of calyx. 



Margin of the calyx obsolete ; petals with an inflexed point ; fruit 

 linear-oblong or ovate-oblong ; ; carpels with 5 obtuse ribs ; carpo- 

 phore free, 2-parted ; vittae very narrow, twice as many as the ribs. 

 % Lvs. 3-parted, lobed and toothed. Umbels compound, with very un- 

 equal rays. Invol. 0. Involucels few-leaved. Fls. white. 



C. CANADBNSIS. DC. (Sison Canadense. Linn.) Hone-wort. 



Lvs. smooth ; Ifts. or segments rhomboid-ovate, distinct, entire or 2 3- 

 lobed, doubly serrate, lateral ones oblique at base ; umbels numerous, irregular, 

 axillary and terminal. Common in moist woods. Stem erect, 1 2f high. Lower 

 petioles 2 6' long, clasping. Leaflets 3, 2 3' long, 1 2' wide, petiolulate. 

 Umbels paniculate, of 3 5 very unequal rays. Umbellets of 4 6 unequal 

 pedicels and minute involucels. Flowers small, white. Fruit near 3" long, 

 oblong-elliptic. Jl. 



10. ZIZIA. Koch. 



Calyx margin obsolete or minutely toothed ; petals carinate, apex 

 acuminate, inflexed ; fruit roundish or oval, didymous ; carpels 5- 

 ribbed, lateral ribs marginal ; intervals with 1 3 vittse, commis- 

 sure with 2 4 ; carpophore 2-parted ; seeds plano-convex. % Lvs. 

 divided. Umbels perfect. Invol. 0. Involucels few-leaved. Fls. yellow. 



1. Z. AUREA. Koch. (Smyrnium. Linn. Thaspium. Nutt. ?) Golden Alexanders. 



Lvs. biternate ; Ifts. oval-lanceolate, serrate; umbelkts with short rays. 

 Hills and meadows, U. S. and Can. Stems 1 2f high, branching above, rather 

 slender, erect, hollow, angular-furrowed, smooth as well as every other part of 

 25 



