AMMIACEAE. 259 



or oblong, flattened laterally. Carpel with 5 filiform 

 bristly primary ribs and 4 prominent winged secondary 

 ones, with barbed or hooked bristles. Stylopodium 

 thick, conic. Oil-tubes solitary in the intervals under 

 the secondary ribs, 2 on the commissural side. Seed- 

 face deeply sulcate. 



1. C. microcarpa H. & A. Erect, slender, 1-3 dm. high, more or 

 less hispid; leaves much dissected, the segments small; umbels at 

 the ends of the stem and branches, very unequally 3-6-rayed; in- 

 volucre of foliaceous divided bracts; involucels of entire or somewhat 

 divided bractlets; rays slender, 7.5 cm. long or less; pedicels very 

 unequal; fruit oblong, 4-6 mm. long, armed with rows of hooked 

 prickles; the primary lateral ribs near margin of commissural face. 



Frequent in sandy or stony places in the valleys and mountains 

 below the pine belt. 



2. C. nodosa Hudson. Stems erect with few branches, retrorsely 

 scabrous; leaves pinnate; leaflets bipinnately dissected; umbels 

 scattered along the stems opposite the leaves on very short peduncles, 

 simple or with supplementary short proliferous umbel; fruit 1-4 

 mm. long, the outside of the umbel with the exterior carpel densely 

 covered with hooked bristles, the inner carpel as well as the inner 

 fruits smooth or with tubercles. 



Oak Knoll, near Pasadena, McClatchie. 



7. APIASTRUM Nutt. 



Very slender smooth branching annuals, with finely 

 dissected leaves having filiform or linear segments, and 

 small white flowers in naked unequally few-rayed umbels. 

 Calyx-teeth obsolete. Fruit ovate or cordate, with 

 obscure or obsolete ribs, more or less tuberculate. Carpel 

 with thin pericarp. Stylopodium minute, depressed; 

 styles short. Oil-tubes solitary in the intervals and 

 beneath the ribs, 2 on the commissural side. Seed-face 

 narrowly concave or sulcate. 



1. A. angustifolium Nutt. Slender, 0.5-3 dm. high, usually 

 much branched; leaves 2.5-5 cm. long, biternately or triternately 

 divided, with linear or nearly filiform segments; umbels sessile; 

 rays from 2.5 cm. long to wanting; pedicels 12 mm. long or wanting; 

 fruit with narrow commissure, cordate in outline, 1 mm, long. 



Common in sandy soil in the foothills and valleys. 



8. CONIUM L. Poison Hemlock. 



Tall biennial glabrous herbs with spotted stems, pin- 

 nately decompound leaves, and small white flowers in 

 compound many-rayed umbels. Involucre and involu- 



