20 seeds. Ipomoea alba. Tender perennial in zone 8-11. 
 
Moonflower Vine. Grown as a annual in cooler climates.
 
Other latin names include Ipomoea noctiflora, Calonyction album, and Calonyction aculeatum
 
Height 10 feet. Spacing 12 inches.
 
Sowing Moonflower Seeds:
 
Nick seeds and soak overnight. Sow outdoors after the last frost date, 1/4 inch deep. Start indoors 4 weeks early in short summer areas. Full sun. 
 
Picture courtesy of Diane's Flower Seeds