858 AMMIACEAE 



Fruit not notched at the apex. 13. MUSENIOPSIS. 



Fruit notched at the apex. 12. ERIGENIA. 



Seed-face flat or nearly so : plants evidently caulescent (except 



Phettoj)terus). 



Fruit without ribs, spiny. 4. SANICULA. 



Fruit ribbed, spineless. 



Carpels with prominently winged ribs. 36. PHELLOPTERUS. 



Carpels with wingless ribs. 



Ribs filiform. 23. TAENIDIA. 



Ribs corky, at least the lateral ones. 



Oil-tubes continuous around the seed cavity. 14. BUPLEURUM. 



Oil-tubes 2-3 in the intervals. 25. SIUM. 



1. HYDROCOTYLE L. 



Perennial herbs of damp situations, with creeping stems. Leaves alternate, one at a 

 node, with long petioles ; blades entire or lobed, palmately nerved, sometimes peltately 

 attached to the petiole. Bracts of the involucre obsolete, or wanting. Flowers perfect or 

 unisexual, inconspicuous, in simple or proliferous peduncled umbels. Sepals manifest. 

 Petals white, acute, valvate. Disk flat or nearly so. Fruit lenticular, laterally flattened, 

 orbicular or depressed, smooth : carpels with 5 primary distinct ribs, without large oil- 

 tubes but a layer of oil-bearing tissues beneath the epidermis. Seeds lenticular. 

 MARSH PENNYWORT. WATER PENNYWORT. 



Leaf-blades suborbicular to transversely oblong, peltate. 



Fruit notched at the base and the apex at maturity : intermediate ribs corky. 



Umbels not proliferous at least not normally so. 1. H. umbellata. 



Umbels or most of them proliferous. 



Peduncle produced beyond the first umbel as a single rachis, bearing one 



or more umbels beyond it. 



Fruit between 2 and 3 mm. broad : dorsal ribs obtuse. 2. H. prolifera. 



Fruit between 3 and 4 mm. broad : dorsal ribs acute. 3. H. Canbyi. 



Peduncle produced beyond the first umbel branching and bearing sev- 

 eral more or less proliferous umbels. 4. H. Bonariensis. 

 Fruit rounded at the base and the apex or cuneate at the base : intermediate 



ribs not corky, very slender. 

 Fruit rounded or truncate at the base, not cuneate. 



Fruit sessile or nearly so. 5. H. verticiUata. 



Fruit pedicelled. 6. H. australis. 



Fruit cuneate at the base. 7. H. cuneata. 



Leaf-blades reniform to suborbicular, not peltate. 



Umbels long-peduncled : leaf-blades deeply lobed. 8. H. ranunculoides. 



Umbel nearly sessile : leaf-blades shallowly lobed. 9. H. Americana. 



1. Hydrocotyle umbellata L. Rootstock producing tubers on its descending 

 branches : leaf-blades peltate, suborbicular, 25 cm. broad, crenate or crenate-lobed : pe- 

 duncles as long as the petioles or longer : umbels many-flowered, normally not proliferous : 

 pedicels 4-12 mm. long: fruit 2 mm. long, about 3 mm. broad, notched at the base and 

 apex, the prominent dorsal ribs obtuse. 



In swamps and meadows, Massachusetts to Minnesota, California, Florida, Texas and Mexico. 

 Also in the West Indies. Spring to fall. 



2. Hydrocotyle prolifera Kellogg. Rootstocks producing tubers on descending 

 branches: leaf-blades peltate, suborbicular, 2-5 cm. broad, crenate : peduncles as long as the 

 leaves or longer : umbels commonly proliferous, the whorls with 5-20 flowers : peduncles 

 prolonged beyond the first umbel : pedicels slender, 2-6 mm. long : fruit between 2 and 3 

 mm. broad, slightly notched at base and apex, the dorsal ribs obtuse. 



In low grounds, Texas to California and Central America. Spring to fall. 



3. Hydrocotyle Canbyi Qoult. & Rose. Rootstocks sometimes tuberous at the joints : 

 leaf-blades peltate, suborbicular, 1.5-4 cm. broad, shallowly crenate-lobed : peduncles 

 shorter than the leaves or longer : umbels generally proliferous, the whorls 3-9-flowered : 

 pedicels slender, 1-4 mm. long : fruit between 3 and 4 mm. broad, slightly notched at base 

 and apex, the dorsal ribs acute. 



t ln damp sandy soil, New Jersey to Maryland and perhaps to Florida. Spring to fall. 



4. Hydrocotyle Bonari6nsis Lam. Kootstocks often greatly elongated : leaf-blades 

 depressed orbicular or orbicular-reniform, 3.5-9. 5 cm. broad, shallowly several-many-lobed, 

 the lobes crenate : petioles and peduncles 6-11 cm. long or sometimes greatly elongated : 

 umbels proliferous and branching, the whorls often many-flowered : pedicels variable, some- 

 times 2 cm. long : fruit 2 mm. long, about 3 mm. wide, slightly notched. 



In waste grounds and on ballast, North Carolina to Florida and Texas. Also in Central and South 

 America. 



5. Hydrocotyle verticillata Thunb. Rootstocks much elongated : leaf-blades peltate, 

 suborbicular or oval, 1-6 cm. broad, shallowly crenate : peduncles much shorter than the 



