Genetic identity and phylogenetic relationships of invasive brooms in California Annabelle Kleist and Marie Jasieniuk, UC Davis Department of Sciences

Background Objectives Results The horticultural industry introduces and distributes large numbers of non-native Overall Goal: Elucidate the identity and origins of invasive into new areas and is a pathway for plant invasions. Horticulturally- brooms in California introduced invaders are often difficult to identify due to hybridization among Specific Objectives: ornamental cultivars and naturalized populations. Intra- and inter-specific hybrid identification is critical for invasive management. This is especially true for 1. Identify which species are being sold by the horticultural industry biological control programs because incorrect identification of hybrids can lead to and which species comprise invasive populations Sweet ineffective biocontrol and/or searches for biocontrol agents outside of native 2. Determine whether hybridization between ornamental cultivars, broom clade ranges. species, and populations in natural areas has occurred

French Study System: Brooms Materials and Methods broom French clade : Cytisus Overview: broom (Scotch broom) clade • Legumes in the tribe Phylogenetic analyses of nuclear and chloroplast DNA sequence data Genisteae (~450 species) were used to determine relationships of invasive and ornamental (French broom) • Invasive brooms belong to genera brooms to each other and to brooms from the native range. Cytisus, Genista, and Spartium Spartium (Spanish broom) Fig 2. ETS 50% majority rule Fig 3. tRNA-leu 50% majority rule French broom: Genista monspessulana Sampling: Maximum Parsimony tree Maximum Parsimony tree • Native Range: Mediterranean Region Invasive population French broom clade: • Introduction to CA: initial introduction ~1850 in San Francisco • 23 invasive brooms from Landscape planting Contains majority of invasive French broom from California and • Current distribution: 23 counties in CA throughout CA Individual from nursery G. monspessulana and G. canariensis Sweet broom: Genista racemosa • 6 landscape plantings Sweet broom clade: • Ornamental plant currently available in CA • 6 plants from horticultural Contains all sweet broom, 3 urban invasive broom samples, G. • Putative close relative of French broom industry stenopetala, and G. maderensis • Morphological similarities Scotch broom: • Samples from botanical • Sold under a variety of scientific names Invasive “Scotch broom” with some similarities to French broom • Including: Cytisus spachianus, Genista stenopetala ssp. gardens and arboreta clusters with French broom for tRNA-leu and with Scotch broom spachiana, and Genista canariensis worldwide for ETS

Predictions Fig 1. French broom and sweet broom collection locations. 1. The current taxonomic status of ornamental and invasive Molecular Tools: brooms in CA is confused. Conclusions: • Multiple species are being sold as “sweet broom” PCR amplification and DNA sequencing: 1. Most of the invasive French broom in CA is either G. • Invasive French broom populations are comprised of multiple • nuclear ETS region closely related species monspessulana, G. canariensis, or a hybrid between the two • chloroplast tRNA-leu region 2. Hybridization occurs between invasive French broom and 2. Ornamental sweet broom most likely contributes directly or via hybridization to invasive broom populations ornamental sweet broom. Phylogenetic Analyses: 3. Sweet broom individuals are present in invasive 3. Hybridization between French and Scotch broom can occur in Maximum parsimony tree constructed using PAUP* populations, particularly in urban invasions natural populations