Family: Asteraceae (Compositae) Vernacular names. Black jack, cobbler's pegs, hairy beggarticks, Spanish needles (En). Bidens pilosa is a cosmopolitan weed, originating from South America and common in all tropical. Blackjack. Scientific names: Bidens Pilosa. 1. BLACKJACK. Where it grows. A wild herb . It is a common weed in agricultural fields with rich soil, but it is not. Blackjack Weed Killer, Black Jack® | Semillas de marihuana Sweet Seeds® Preferred Scientific Name; Bidens pilosa. Preferred Common.