350 UMBELLIFERAE (PABSNIP FAMILY) 



4. Musineon vaginatum Rydb. Mem. N. Y. Bot. Gard. 1: 288. 1900. 

 Steins becoming slender, glabrous, more or less purple tinged: basal leaves 

 twice or thrice temate; stem leaves two or three: involucre none; involu^iels 

 of linear bractlets: petals white, sometimes tinged with yellow: fruit slightly 

 scabrous. — Montana. 



5. Musineon tenuifoliiun Nutt. 1. c. Acaulescent, somewhat ■ caespitoae'' 

 glaucous: leaves tripinnatifid, with narrowly linear segments: peduncles much 

 longer than the leaves, 1-2 dm. long; umbel 12-20-rayed: fruit nearly glabrous, 

 3-4 mm. long; oil-tubes large, 2-3 in the intervals; flowers apparently some- 

 times white. — Eastern Wyoming and adjacent Nebraska and Dakota. 



6. BUPLEURUM L. 



Annuals or perennials, with simple, entire, clasping or perfoliate stem leaves, 

 with or without an involucre, and involucels of 5 or more ovate bractlets. 

 Calyx-teeth obsolete. Fruit oblong, flattened laterally, with rather broad com- 

 missure. Carpel with equal very slender or prominent ribs; stylopodiu^n prom- 

 inent and flat; oil-tubes wanting or continuous about the seed cavity. 



Flowers yellow 1. B. americanum. 



Flowers purple 2. B. purpureum. 



1. Bupletirum americanum C. & R. Rev. N. Am. Umbell. 115. 1888. 

 Basal leaves linear-lanceolate; cauline ones very variable, oblong to linear, 

 more or less clasping: rays unequal, 1.5-5 cm. long; pedicels short. B. ranun- 

 culoides. — Wyoming to Alaska. 



2. Bupleurum purpureum Blankinship, Mont. Agric. Coll. Sci. Studies 

 1 : 89. 1905. Differs from B. americanum in its low subacaulescent habit, 

 shorter leaves, wider obtuse bractlets of the involucels, smaller dark purple 

 flowers, shorter fruit with fewer oil-tubes in the intervals, and in its alpine 

 situation. — High mountains of Montana. 



6. ZIZIA Koch 



Smooth perennials of open prairies and upland meadows, with simple to 

 ternately compound leaves, no involucre, involucels of small bractlets, yellow 

 flowers, and the central fruit of each umbellet sessile. Calyx-teeth prominent. 

 Fruit flattened laterally, ovate to oblong, glabrous. Carpel with filiform ribs; 

 stylopodium wanting; styles long; oil-tubes large and solitary in the broad 

 intervals, 2 on the commissural side, and a small one in each rib. Seed terete, 

 sulcate beneath the oil-tubes. 



1. Zizia cordata (Walt.) Koch, DC. Prodr. 4: 100. 1830. Basal leaves 

 mostly long-petioled, cordate or even rounder, crenately toothed, very rarelj'; 

 lobed or divided; stem leaves simply temate or quinate; the leaflets ovate to 

 lanceolate, serrate, incised, or even parted : fruit ovate, 3 mm. long. Thaspiim 

 trifoliatum in part. — ^Throughout our range and across the continent. . i 



7. HARBOURIA C. & R. 



Glabrous perennials, with 1-3 leaves which are ternately decompound and 

 with narrowly linear or filiform segments, involucre and involucels of few 

 subulate bracts, and long-pedimcled umbels (mostly in pairs) of yellow flowers. 

 Calyx -teeth evident. Fruit flattened laterally, ovate, with narrow commis- 

 sure, tuberoulate-roughened. Carpel with equal, obtuse, broad, very promi- 

 nent ribs, a small group of strengthening cells in each; the narrow commissure 

 prominently corky-thickened, partly divided by a groove; stylopodium de- 

 pressed or wanting; oil-tubes large, solitary in the intervals, 2 on the commis- 

 sural side. Seed section nearly round. 



1. Harbouria trachypleura (Gray) C. & R. Rev. N. A. Umbell. 125. 1888. 



