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      Part 1      Part 2      Cystoliths      Pollinators 1       Pollinators 2       Pollinators 3       Pollinators 4       Pollinators 5  
Fig Pollinators At Palomar College 5
The Remarkable Mexican Rock Fig (Ficus petiolaris)
© W.P. Armstrong Updated 15 November 2025
Ficus petiolaris = F. palmeri & F. brandegeei

Mexican Rock Fig Ficus petiolaris in Vista, California

F. petiolaris With Wasps & Viable Seeds by Julian Duval in Vista, CA

Close-up view into syconium of Ficus petiolaris showing ovaries of female flowers & anthers of male flowers. Black-headed males rule out Blastophaga psenes, pollinator wasp of the common, edible fig (Ficus carica). The native pollinator for Ficus petiolaris (Pegoscapus) is in San Diego County. The Mexican rock fig (Ficus petiolaris) is a popular fig for botanical gardens and private collections (including bonsai) in southern California. And the beautiful canyons in Baja California are a popular destination for desert travelers. It is quite possible that Pegoscapus was introduced in southern California, like 4 other species of fig wasps at Palomar College.

If the ripened ovaries within Ficus syconia do not contain a wasp larva, they typically develop into minute, one-seeded drupelets. The actual seed is surrounded by a sclerified endocarp layer, the inner layer of the drupelet (fruit) wall. Some references refer to the tiny one-seeded fruits as nutlets or achenes, but they are technically drupelets.

Ficus petiolaris in Palomar College Arboretum

Two views of Ficus petiolaris in the Palomar College Arboretum. The tree is surrounded by dense coastal sage scrub near large outcrop of monzogranite bedrock.

  33.150312 N, -117.180079 W;  

Many references state that males also perform another important task before they die: Chewing escape hole in wall of syconium through which females leave; however, Eva Maria Piedra-Malagon, et al. "Syconium Development in Ficus petiolaris & Their Relationship With Pollinator & Parasitic Wasps," Canadian Science Publishing (2018), states that escape holes are cut at ostiole end through overlapping bracts. This is what I observed in the Ficus petiolaris syconia I examined.

Ovaries with an exit hole once housed a developing Pegoscapus wasp. A gravid female entered the syconium at an earlier receptive state and oviposited in many of the ovaries of female flowers. She also introduced pollen into the receptive syconium at that time. In the typical fig life cycle she inserts her ovipositor down the style; however, she can only reach the ovary & deposit an egg in the short-style flowers. She is unable to reach the ovary & lay an egg in long-style flowers, so these ovaries develop into minute one-seeded fruits called drupelets. The fig tree produces literally thousands of fig wasps and viable seeds. The remarkable, genetically controlled style length insures seed production and wasp pollination, both essential for survival & perpetuation of the fig tree.

Ficus petiolaris 2-porate pollen grains are very small, about 10-20 micrometers in length. Each oval grain has a pore at each end, typical of fig pollen. Olympus compound microscope, magnification 1000x. [Human red blood cells are about 8 micrometers in diameter.]

Ficus petiolaris = F. palmeri

Imature Syconia 4 Oct 2025
(On Very Long Petioles)

Ficus petiolaris in Baja CA

  Wild Figs (Higueras) in Baja California