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..
Aquatic herbs, with horizontal perennial rootstocks, floating leaves and showy flowers. Sepals 4. Petals , imbricated in few to many series, inserted on the ovary, gradually passing into stamens; stamens ∞, the exterior with large petaloid filaments and short anthers, the interior with linear filaments and elongated anthers. Carpels ∞, united into a compound pistil with radiating linear projecting stigmas. Fruit globose, covered with the bases of the petals, ripening under water. [A spring of Parnassus.]
About 40 species, of wide geographic distribution. Type species: Castalia pudica Salisb.
Flowers 4'-9' broad, not fragrant; leaves orbicular, green both sides.
Flowers 1'-1 1/2' broad not fragrant; leaves oval.
Kew. 2: 227. 1789. Castalia pudica Salisb. in Konig. &
Am. Sept. 369. 1814.
Rootstock thick, simple or with few branches. Leaves floating, orbicular or nearly so, 4'-12' in diameter, glabrous, green and shining above, purple and more or less pubescent beneath, cordate-cleft or reniform, the sinus open but sometimes narrow; petioles and peduncles slender, with 4 main air-channels; flowers white, or sometimes pink, 3'-6' broad, fragrant; petals numerous, in many rows, narrowly oblong, obtuse; fruit globose, or slightly depressed; seeds stipitate, oblong, snorter than the aril.
In ponds and slow streams, Newfoundland to Manitoba, south to Florida, Louisiana and Kansas. Toad-lily. June-Sept.
Rootstock thick, with numerous lateral tuberous-thickened branches, which become detached and propagate the plant. Leaves orbicular, 5'-12' in diameter, floating, sometimes slightly pubescent beneath, green both sides, the veins very prominent on the lower surface; sinus open or closed; petioles stout; flowers pure white, 4'-9' broad, inodorous or very slightly scented; petals oblong, in many cows, broader than those of C. odorata, obtuse; fruit depressed-globose; seeds globose-ovoid, sessile, longer than or about equalling the aril.
Nymphaea tetragona Georgi, Reise in Russ.
Reichs, I: 220. 1775. Castalia pygmaea Salisb. Parad. Lond. pl.
68. 1807. C. Leibergii Morong. Bot. Gaz. 13: 134.
1888. Castalia tetragona Lawson, Trans. Roy.
Soc. Canada 6: Sec. IV. 112. 1888.
Leaves floating, oval or oblong, 2'-4' long, 1 1/2' - 3' wide, green above, green or purplish beneath, the basal lobes acute or rounded; sinus open, narrow; petioles and peduncles nearly or quite glabrous; flowers white, inodorous, 1'-2' broad; petals in about 2 rows, faintly striped with purple, obtuse or acutish, oblong or obovate, thin, about the length of the sepals.
In the Misinaibi River, Ontario (R. Bell); in ponds along the Severn River, Keewatin (J. M. Macoun); near Granite Station, northern Idaho (Leiberg). Also in Siberia, Japan and the Himalayas. Summer.