Flowering of three species of Brodiaea in relation to bulb size and source

Abstract

Flowering of Triteleia bridgseii Greene, Triteleia ixiodes Greene, and Dichelostemma Ida-maia Greene was investigated using corms of various sizes collected from the natural habitat as well as those from a cultivated field. Regardless of species, flowering percentage of all plants in the Brodiaea complex increased, the number of florets per scape increased, and the forcing time decreased as the size of the mother corm increased. The length of the flowering scape is species specific: 18–20 cm for T. ixiodes, 40–45 cm for T. bridgseii, and 40–50 cm for D. Ida-maia, and is unaffected by the size of the mother corm. Except for large corms, T. bridgseii and T. ixiodes generally produced only one replacement corm indicating that other means of propagation would be required prior to commercial cut flower production. In contrast, D. Ida-maia readily produced a replacement corm as well as many cormlets from each mother corm. The minimum corm size for 100% flowering varies with species and the source of the corms. All T. bridgseii corms >0.8 g flowered, whereas for D. Ida-maia, a minimum corm size of 3 g was required. In T. ixiodes, the source of the corms affected the flowering of the corms. All T. ixiodes corms from the natural habitat weighing >0.3 g flowered, whereas for those from the cultivated field, a minimum corm size of 3.6 g was required. Data for T. ixiodes, thus, suggest that environmental conditions during which the corms are produced may play a significant role in the flowering potential of a species.