312 AMMIACEAE. 



Leaf-blades orbicular or ovate, merely toothed ; flowers white. 



Involucre none. 1. Hydrocotyle. 



Involucre conspicuous. 2. Centella. 



Leaf-blades pinnatifid into filiform segments. 



Fruit margined, flat ; flowers yellow. 3. Anethum. 



Fruit not margined. 



Flowers yellow. 4. Foenicidum. 



Flowers white. 5. Helosciadium. 



1. HYDROCOTYLE L. Sp. PL 234. 1753. 



Perennial herbs, prostrate and commonly rooting at the joints, with 

 palmately lobed or veined, often peltate leaves, the bases of the petioles with 

 2 scale-like stipules, and small white flowers in umbels opposite the leaves. 

 Bracts of the involucre few, or none. Calyx-teeth minute. Petals entire. 

 Disk flat. Fruit laterally compressed, orbicular or broader than high. Carpels 

 with 5 primary ribs, the lateral ones usually curved; no large oil-tubes but 

 an oil-bearing layer of tissue beneath the epidermis. [Greek, water-cup.] 

 About 75 species of wide distribution. Type species: Hydrocotyle vulgaris L. 



Plant glabrous. 1. H. verticillata. 



Leaves and inflorescence villous-pubescent. 2. H. hirsuta. 



1. Hydrocotyle verticillata Thunb. Diss. Hydrocot. 5. 1798. 



Glabrous; leaves orbicular, peltate; inflorescence proliferous, 2-5 cm. long; 

 verticils 2-6-flowered; pedicels usually less than 1 mm. long; fruit about 2 mm. 

 long, 3-4 mm. broad, rounded or truncate at each end; intermediate ribs not 

 corky-thickened, the dorsal one acute. 



Wet palmetto-lands, Great Bahama at Barnett's Point ; Andros at Couch Sound : 

 — Bermuda ; .Jamaica ; Cuba ; Hispaniola ; Porto Rico ; Guadeloupe ; southern 

 Africa ; Massachusetts to Florida and Arizona. Recorded by Mrs. Northrop as H. 

 pygmaea Wright. Determination of the Bahama plant is from leaf-specimens only. 

 Whorled Maksh Pennywort. 



2. Hydrocotyle hirsuta Sw. Prodr. 54. 1788. 



Hydrocotyle spicata Lam. Encycl. 3: 153. 1789. 



Stems creeping, rooting at the nodes, very slender, glabrous or nearly so, 

 0.5-3 dm. long. Petioles villous, 1-8 cm. long; leaf-blades suborbicular or 

 reniform, 1-3 cm. broad, crenate, rather deeply cordate, villous on both sides, 

 densely so beneath; spikes peduncled, interrupted, usually longer than the 

 leaves, sometimes 8 cm. long, the peduncles and rachis villous; fruits sessile, 

 glabrous, emarginate at top and bottom, about 1.5 mm. broad. 



Grassy places. New Providence near Nassau : — Cuba ; Hispaniola ; Porto Rico ; 

 Curagao. Hairy Marsh Pennywort. 



Hydrocotyle umhellata L. recorded for the Bahamas by Dolley has not been 

 found by us anywhere in the islands ; Mr. Brace thinks that the reference really 

 applied to Centella asiatica. 



2. CENTELLA L. Sp. PI. ed. 2, 1393. 1763. 



Perennial herbs (some African species shrubby), ours with prostrate s?ems 

 rooting and sending up tufts of petioled leaves at the nodes, together with 

 1-3 long-rayed umbellets of small white flowers, the true umbel sessile. Petiole- 

 bases sheathing. Bracts of the involucels 2-4, mostly prominent. Calyx-teeth 

 none. Disk flat, or slightly concave. Styles filiform. Fruit somewhat flat- 

 tened laterally, rather prominently ribbed, the ribs mostly anastomosing; oil- 

 tubes none. [Latin, diminutive of centrum, a prickle.] About 20 species, of 



