This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", 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..
[Macrocalyx Trew, Nov. Act. Nat. Cur. 2: 330 -332. pl. 7. f. I. Hyponym. 1761.] [Ellisia L. Sp. Pl. Ed. 2, 1662. 1763. Not Syst. Ed. 10, 1121. 1759.] Annual hirsute or pubescent branching slender herbs, with opposite or alternate, pinnately divided or 1-3-pinnatifid leaves, and solitary or racemose small white or bluish flowers. Calyx 5-lobed or 5-parted, spreading, much enlarged in fruit, destitute of appendages in the sinuses. Corolla campanulate or nearly cylindric, shorter than or slightly exceeding the calyx, usually with 5 minute appendages on the tube within, its lobes convolute or imbricated in the bud. Staniens included; anthers oval or oblong. Ovary 1-celled; styles united below; ovules 2-4 on each of the placentae, which are similar to those of the two preceding genera. [Name unexplained.]
About 3 species, natives of North America, the following typical.
Ipomoea Nyctelea L. Sp. Pl. 160. 1753. Polemonium ( ?) Nyctelea L. Sp. Pl. Ed. 2, 231. 1762. Ellisia Nyctelea L. Sp. Pl. Ed. 2, 1662. 1763. Macrocalyx Nyctelea Kuntze, Rev. Gen. Pl. 434. 1891.
Sparingly hirsute-pubescent; stem several times forked, 4'- 12' high. Leaves pinnately divided, petioled, 2'-4' long, ovate-oblong in outline, the upper alternate, the lower opposite, the segments oblong or lanceolate, dentate, entire or lobed; peduncles slender, 1-flowered, opposite the leaves; calyx in flower about 2" long, about equalling the corolla, enlarging, widely spreading and becoming 8"-14" broad in fruit, its lobes lanceolate or ovate-lanceolate, acuminate; fruit at length pendulous; capsule globose, 2"-3" in diameter.
In moist soil, New Jersey to Minnesota, Saskatchewan, Virginia, Nebraska and Kansas. April-July.