UMBELLIFERAE (PARSNIP FAMILY) 349 



3. OROGENIA Wats. 



Dwarf, glabrous, nearly acaulescent plants, from tuberous or fusiform roots, 

 with ternate leaves and linear segments, no involucre, involucels of few lin- 

 ear bractlets, and white flowers in subcompound umbels with very unequal 

 rays. Calyx-teeth minute. Fruit oblong, very slightly flattened laterally, 

 glabrous. Carpel much flattened dorsally, with filiform dorsal and inter- 

 mediate ribs; laterals excessively corky-thickened, involute (that is, extended 

 toward the other carpel, leaving between the commissural faces a cavity, 

 which is divided longitudinally by a thick corky projection from the middle 

 of each face). 



1. Orogenia linearifolia Wats. Bot. King's Rep. 120. 1871. Stem (or 

 scape) slender, rising 2-12 cm. above ground from a deep-seated round tuber: 

 leaves 2 or 3, once or twice ternate upon slender petioles; leaflets entire, 

 2.5-5 cm. long, 2-6 mm. wide, obtuse: umbels 2-10-rayed, with nearly sessile 

 flowers: fruit 3-4 mm. long, lateral ribs and commissural projection rather 

 strongly developed. Southwestern Colorado and to the far northwest. 



4. MUSINEON Raf. 



Glabrous or scabrous, dwarf, resiniferous, dry-ground perennials, from thick 

 elongated roots, acaulescent or dichotomously branching at base, with pin- 

 nately decompound leaves, no involucre, involucels of a few narrow bractlets, 

 and yellow flowers. Calyx-teeth prominent (in ours). Fruit ovate or ovate- 

 oblong, flattened laterally. Carpel flattened dorsally, with equal filiform ribs 

 and thin pericarp with no distinct strengthening cells; carpophore entire; 

 stylopodium depressed ; oil-tubes usually 3 in the intervals, very unequal in 

 size (middle one largest), 2-4 on the commissural side. Seed face broadly 

 concave. Musenium. 



Stems usually dichotomously branching from the base; leaf-segments 



toothed. 

 Fruit smooth; stems glabrous. 



Peduncles slender, scarcely longer than the leaves . . . 1. M. divaricatum. 

 Peduncles stout, 2-3 times as long as the leaves . . . 2. M. pedunculatum. 

 Fruit scabrous. 



Stem scabrous 3. M. Hookeri. 



Stem smooth 4. M. vaginatum. 



Acaulescent, the simple peduncles exceeding the leaves; flowers yel- 

 low or sometimes white 5. M. tenuifohum. 



1. Musineon divaricatum (Pursh) C. & R. Bot. Gaz. 20: 259. 1895. De- 

 cumbent, glabrous: leaves bipinnatifid, with winged rachis; segments 3-5- 

 toothed: peduncles 5-12. 5 cm. long; umbel 10-25-rayed; rays 6-18 mm. long; 

 pedicels short: fruit smooth, about 4 mm. long; oil-tubes 3 in the intervals, 

 with accessory ones beneath the ribs, 4 on the commissural side: seed terete, 

 with rather deeply concave face. From Colorado and Nebraska to Alberta 

 and Assiniboia. 



2. Musineon pedunculatum A. Nels. Bull. Torr. Bot. Club 25: 225. 1901. 

 Root large, fleshy: stems nearly acaulescent: leaves thick, usually ternate ; the 

 segments pinnate or bipinnate, ovate in outline, the alternate segments broad 

 and short, variously cut and toothed: peduncles prostrate, stout, 12-20 cm. 

 long, 2-3 times as long as the leaves; umbel 12-20-rayed; rays 15-25 mm. 

 long; pedicels 1-4 mm. long: fruit smooth; oil-tubes 3 in the intervals and 4 

 on the commissural side: seed slightly flattened dorsally, with plane face. 

 Naked clay soils ; central Wyoming. 



3. Musineon Hookeri (T. & G.) Nutt. T. & G. Fl. 1 : 642. 1840. Resembling 

 M . divaricatum, but more or less scabrous throughout: fruit scabrous, smaller, 

 2-3 mm. long, with more prominent ribs; oil-tubes mostly solitary in the in- 

 tervals, often with smaller accessory ones Li the intervals or beneath the ribs, 

 2 on the commissural side: seed sulcate beneath the oil-tubes, with more 

 shallow concavity. (Includes both M. trachyspermum and M. anyustifolium 

 Nutt. T. & G. Fl. 1: 642. 1840.) From Colorado to Canada. 



