This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
[Polytaenia DC. Mem. Omb. 53. pl. 13. 1829. Not Polytaenium Desv. 1827.]
[Pachiloma Raf. New Fl. N. A. 33. 1836. Not Pachyloma DC. 1828.]
[?Phaiosperma Raf. loc. cit. 32. 1836.]
Perennial, nearly glabrous herbs, with pinnately decompound leaves, and compound umbels of yellow flowers. Involucre none, or rarely of 1-2 linear bracts. Involucels of a few subulate pubescent deciduous bracts. Calyx-teeth prominent, triangular. Petals obovate-cuneate, with a long incurved tip. Stylopodium none. Fruit oval or obovate, much flattened dorsally, thick and corky; dorsal and intermediate ribs obscure, the lateral ones with thick wings which form a broad margin to the fruit, and are nerved toward the outer margin; oil-tubes 12-18, contiguous, with numerous smaller ones irregularly disposed in the thick pericarp. Seed flat. [Greek, many-fillets, or oil-tubes.]
A monotypic genus of cential North America.
Polytaenia Nuttallii DC. Mem. Omb. 53. pl. 13, 1829.
Pleiotaenia Nuttallii Coult. & Rose, loc. cit. 448. 1909.
Stem slightly scabrous, leafy, 1°-3° high; roots fusiform. Leaves petioled, or the uppermost smaller and sessile, pinnate, the segments deeply pinnatifid or parted, 1-3' long, the lobes ovate, oblong or obovate, dentate or entire; umbels 6-12-rayed, \'-2\' broad; rays scabrous, 1/2-2 1/2' long; pedicels finely pubescent, 1"-2" long; fruit glabrous, 3"-5" long, 2 1/2"-3 1/2" broad, 1/2" thick, the margins obtuse, the central part of both carpels depressed when dry.
Dry soil, Michigan and Wisconsin to Tennessee, Alabama, Kansas, Louisiana and Texas. April-May.
14. AN╚THUM [Tourn.] L. Sp Pl. 263. 1753.
Annual glabrous erect herbs, with finely dissected leaves, and large compound umbels of yellow flowers. Involucre and involucels wanting. Fruit oblong to elliptic, dorsally much flattened, the lateral ribs winged, the dorsal ones slender, sharp. Oil-tubes solitary in the intervals. [The ancient name.]
Two Asiatic species, the following typical.
Anethum graveolens L. Sp. Pl. 263. 1753.
Stem usually branched above, striate, 1°-3° high. Leaves very finely dissected into almost filiform segments, similar to those of Foe-niculum, the sheathing petioles strongly nerved and scarious-margined; umbels up to 6' broad, several-many-rayed, the rays 3' long or less; fruiting pedicels s"-8" long; fruit about 3" long, 1 1/2" wide.
Waste grounds, Connecticut to Virginia. Also in the West Indies. July-Sept.