42 Phytologia (Jan 5, 2016) 98(1) Ficus microcarpa (Moraceae) naturalized in Southern California, U. S. A.: Linking plant, pollinator, and suitable microhabitats to document the invasion process RICHARD E. RIEFNER, JR. Research Associate, Rancho Santa Ana Botanic Garden 1500 North College Avenue Claremont, California 91711-3157, U.S.A.
[email protected] ABSTRACT Ficus microcarpa is native to temperate and tropical Asia, Australasia, and Pacific regions. It is a popular ornamental tree grown in many warm temperate, subtropical, and tropical regions of the world, where it is widely known to escape from cultivation. It is reported here as being naturalized in Los Angeles, Orange, Riverside, San Diego, and Ventura counties, southern California. The invasive spread of F. microcarpa follows the introduction of its host-specific pollinating wasp, Eupristina verticillata; E. verticillata was first reported for California in 1994 from Arcadia, Los Angeles County. The wasp introduction reunited the F. microcarpa host plant–E. verticillata obligate pollinator mutualism thereby enabling the reproduction and naturalization of both organisms in California. A map showing the current distribution of F. microcarpa, citation of voucher specimens, and photographic documentation are provided. Published on-line www.phytologia.org Phytologia 98(1):42-75 (Jan 5, 2016). ISSN 030319430. KEY WORDS: Ficus microcarpa, biological invasions, California, epiphytes, Eupristina verticillata, fig wasps, halophytes, invasive plants, mutualisms, ornamental horticulture, urban weeds. _______________________________________________________________________________________ Ficus (Moraceae) is one of the largest and most diverse genera of flowering plants. Ficus species occur primarily in subtropical and tropical regions around the world (Berg & Corner 2005). Members of the genus are treated within six subgenera based primarily on their differences in habit and inflorescence morphologies (Berg 2003), and species-specific wasp-dependent pollination syndromes (van Noort & Rasplus 2015).