606 HALORAGIDACEAE 



2. M. verticillatum L. Stem 3-20 dm. long; leaves flaccid, verticillate in 

 3's or 4's, 1.5-4 cm. long, pinnatifid, the rachis usually broader than the filiform 

 divisions; floral leaves or bracts similar, but shorter and firmer, 6-20 mm. long; 

 stigmas elongate, recurved; sepals of the staminate flowers pale green or pink- 

 ish. Still water and slow streams: Que. N.Y. Neb. Ida. B.C. Plain 

 Submont. Je-Au. 



2. HIPPURIS L. MARE'S-TAIL. 



Aquatic perennial herbs, with simple stems. Leaves narrow, entire, verti- 

 cillate. Flowers perfect, axillary. Hypanthium adherent to the ovary, with a 

 minute entire limb. Sepals and petals none. Stamen solitary. Pistil soli- 

 tary; style filiform, stigmatic its whole length, placed in a groove of the anther; 

 Fruit 1 -celled, 4-seeded. 



1. H. vulgaris L. Stem simple, 2-6 dm. high; leaves in whorls of 6's-12's, 

 linear, acute, 1-3 cm. long; stamen with a short thick filament and large anther; 

 fruit nearly 2 mm. long. Swamps and ponds: Greenl. N.Y. Neb. N.M. 

 Calif. Alaska; Eurasia. Plain Mont. Je-Au. 



FAMILY 93. AMMIACEAE. CARROT FAMILY. 



Herbs, with usually hollow stems. Leaves alternate, usually compound 

 or decompound, rarely simple, with dilated sheathing leaf-bases. Flowers 

 perfect or polygamous, in simple or compound umbels, or rarely in heads or 

 head-like clusters, the umbels commonly subtended by involucres and invo- 

 lucels, consisting of several bracts or bractlets. Hypanthium adnate to the 

 ovary. Sepals 5, usually small. Petals 5, usually with an inflexed tip, 

 often emarginate. Stamens 5, inserted on an epigynous disk; anthers versa- 

 tile. Gynoecium of 2 united carpels, each 1-ovuled. Styles 2, distinct, 

 borne on a more or less developed thickened base (stylopodium} . Fruit 

 of two 1-seeded carpels, separating at maturity; each carpel usually with 

 5 principal ribs, sometimes with 4 secondary ribs; the faces where the two 

 carpels meet are called the commissures, and the sinuses between the ribs, 

 intervals; the pericarp usually containing oil-tubes in the intervals and on 

 the commissural side; some or all the ribs often winged. 



A. Fruit with the secondary ribs most prominent, in ours ellipsoid, armed with prickles; 



oil-tubes under tne secondary ribs; leaves pinnately compound. 

 Stylopodium obsolete; calyx-teeth obsolete; fruit flattened dorsally. 



1. DAUCUS. 

 Stylopodium conical; calyx-teeth prominent; fruit flattened laterally. 



2. CAUCALIS. 



B. Fruit with primary ribs only, or ribs wanting; oil-tubes (rarely lacking) in the inter- 



vals between the libs. 



I. Fruit scaly or spiny. 



Fruit ovoid, covered with hyaline scales or tubercles; leaves coriaceous, spinosely 

 toothed or divided ; flowers in dense heads. 3. ERYNGIUM. 



Fruit with hooked spines, subglobose; flowers in simple or compound few-rayed 

 umbels; leaves not spinose, palmately or pinnately divided. 



4. SANICULA. 



II. Fruit not spiny, only bristly on the ribs in Osmorrhiza. 



a. Fruit linear, linear-oblanceolate, or linear-lanceolate in outline. 



Stylopodium present; oil-tubes obsolete in the mature fruit; fruit thickened 

 above; leafy-stemmed plants with aromatic thick roots and ternately 

 decompound leaves with toothed segments. 



Fruit attenuate at the base, bristly on the ribs. 5. OSMORRHIZA. 



Fruit glabrous, obtuse at the base. 6. GLYCOSMA. 



Stylopodium wanting; oil-tubes small but evident; fruit thickest below; 

 acaulescent plants, with globose corms and ternate leaves with linear seg- 

 ments. 7. LEIBERGIA. 



b. Fruit oblong to orbicular in outline. 



1. Fruit not compressed dorsally, terete in cross-section or somewhat com- 

 pressed laterally; wings of the lateral ribs (if present) rarely much 

 broader than those of the dorsal ribs. 

 a - Ribs not conspicuously winged. 



* Ribs at least the dorsal ones filiform or more prominent, but not 

 corky. 



