170 



AMMIACEAE 



few-toothed, 5-15 mm. 

 4. O. MacDougali. 



1. H. trachypleura. 

 1. S. cicutaefoliutn. 



Plant 1-2 dm. high, glabrous; leaflets ovate or lanceolate, 

 long: fruit oblong. 6-7 ram. long. 



21. HARBOURIA Coult. & Rose. 



22. SIUM (Tourn.) L. Water Parsnip. 



23. CICUTA L. Cow Bane, Poison or Water Hemlock. 



Axils of the leaves not bearing bulblets ; leaflets lanceolate. 



Bractlets scarioiis-margined. 1. C. dnicola. 



Bractlets not scarious. 



Fruit orbicular in outline; rootstock usually horizontal or ascending. 



2. C. cagans. 

 Fruit oval in outline; rootstock exceedingly short, erect. 3. C. occidentalis. 



Axils of the leaves (especially the upper ones) bearing bulblets; leaflets narrowly linear. 



4. C. bulblfera. 



24. AULOSPERMUM Coult. & Rose. 



Involucres present. 1. A. glaucum. 

 Involucres wanting. 

 Corolla yellow. 



Rachls of the primary leaf-segments dilated; secondary segments confluent, 



broad, toothed or merely cleft. 2. A. lonqipes. 

 Rachls of the primary leaf -segments not dilated: secondary segments distinct, 



finely dissected into oblong lobes. 3. A. angustum. 

 Corolla not yellow. 



Corolla white. 4. A. ibapevse. 



Corolla purple. 5. A. planosum. 



25. PHELLOPTERUS Nutt. 



Wings of the fruit thin and broad, scarcely rugose. 



Pedimcles even in fruit shorter than the leaves; wings thickened at 



Flowers white; fruit 6-8 mm. long. 1. 



Flowers purple; fruit 10-14 mm. long. 2. 



Peduncles at least in fruit equalling or exceeding the leaves ; wings 



the insertion: fruit more than 8 rom. long. 



Involucels 1-3-nerved; corolla purplish. 



Fruit oblong. 3. 



Prviit orbicular. 4. 

 Involucels 5— 13-nerved. 



Bracts white with green middle; corolla white or pink. 5. 



Bracts and corolla purple. 6. 



Wings of the fruit thick, somewhat corky and rugose. 7. 



the insertion. 

 P. montanus. 

 P. macrocarpus. 

 not thickened at 



P. bulbosus. 

 P. utahensis. 



P. camporum. 

 P. muUinervatus. 

 P. Jonesii. 



C. Rosei. 



C. basalticus. 



C. purpureus 

 C. Betheh. - 



26. CORIOPHYLLUS (M. E. Jones) Rydb. Indian Parsnip. 



Wings thickened at the insertion. 



Leaves ternately bipinnatifld; oil-tubes solitary in each interval. 1. C Jonesii. 



Leaves pinnate, with lobed or divided leaflets; oil-tubes several in eachjnterval. 



Leaves ovate to ovate-oblong in outline; flowers pedicelled. 2. 



Leaves reniform to oblong-cordate in outline; flowers ses.sile. 3. 

 Wings not thickened at the insertion. 



Flowers purplish: oil-tubes on the commissiu-e 8. 4. 



Flowers greenish yellow: oil-tubes on the commissure 4. 5. 



27. PTERYXIA Nutt. 

 Petals yellow. 



Leaves broadly rhombic in outline. 



Dorsal ribs with broad wings. 1. P. foeniculacea. 



Dorsal ribs with narrow wings. 2. P. Elrodi. 

 Leaves oblong or ovate in outline. 



Pirmae very small and distant. 3. P. pelraea. 



Pinnae larger and crowded. 4. P. calcarea. 



Petals white. 5. P. albiflora. 



28. PSEUDOREOXIS Rydb. i. p. bipinnaius. 



29. CYMOPTERUS Raf. 



Umbels dense, globular: petals white; involucre wanting. 

 Involucels of linear to oblong bractlets. 



Ultimate divisions of the leaves Unear or linear-oblong, acutish: fruit orbicular, 



6-8 mm. long. 1. C. acaulis. 



Ultimate divisions of the leaves short, broadly oblong, obtuse; fruit 7-10 mm. long. 

 Bractlets oblong, rarely lanceolate, obtuse; fruit orbiculeir, 8-10 mm. broad; 

 • wings strongly thickened. 2. C. Parryi. 



Bractlets linear or lanceolate, acute; fruit oval, 6—8 mm. broad: wings moder- 

 ately thickened. 3. C. liicidus. 

 Involucels of broad membranous, more or less 3-cleft bractlets; fruit fully 10 mm. 

 long, broadly elliptic. 4. C. Leibergii. 



