Understanding the Reproductive Biology of Angelonia integerrima Spreng. (Plantaginaceae), a Native Southern Brazilian Plant with Horticulturally Desirable Traits

<i>Angelonia</i> Bonpl. (Plantaginaceae) is a neotropical genus of ornamental interest, with some Mexican species already commercialized in the horticultural trade. <i>Angelonia integerrima</i> Spreng. is the only species of the genus native to Southern Brazil, and, despite its high ornamental potential, its reproductive requirements are unknown. Flower features and natural pollination were studied in the field in three localities within Southern Brazil. Pollination was recorded through pictures and videos. The breeding system was studied through controlled pollinations applied to plants excluded from pollinators. Germination was studied under controlled temperatures (20°, 25°, and 30 °C). According to our results, flowers are protandrous and keep their fresh appearance for up to nine days. The flowers produce oils in a pair of trichromes located inside the corolla. The plants are pollinator-dependent and self-compatible. The sole pollinators are oil-gathering solitary bees, <i>Centris trigonoides Lepeletier</i>, <i>1841</i> and <i>Centris</i> sp. (Apidae), that pollinate the flowers while collecting the floral oils. Germination proceeds better at 25 °C, reaching success of 50%. The domestication of this plant for horticultural purposes in Southern Brazil would be desirable not only for its ornamental characters but also for ecosystemic reasons since the species is already adapted to environmental conditions and its flowers offer resources for native, solitary bees.