Fig. 3

Specialized idioblast cells and cavities containing oxalates, and potential endophytic bacteria within Cape Oxalis host plants. a Longitudinal sections through bulb fleshy leaves with idioblasts containing oxalates (crystals) (i,ii) and a cross section of empty cavities (iii). b Cross sections of photosynthetic leaves with cavities containing oxalates (i,ii) and empty cavities with an epithelial lining (iii). c Cross sections of dormant (i) and recalcitrant (ii) fruit capsules with cavities containing oxalates. d Longitudinal sections of recalcitrant seeds with multiple cavities in the cotyledons (i), a cavity containing oxalates (ii) and empty cavities with epithelial lining (iii). e Confocal staining of cross sections of sterilized seeds indicating bacteria (bright green rods, circled in white) inside cavities. Original red-and-green confocal images supplied in Additional file 3: Figure S3. EB = endophytic bacteria, CO = cotyledon, CR = crystals, CV = cavities, HY = hypocotyl, ID = idioblasts or idioblast cavities, OX = oxalates, PL = plumule, S = seeds. A key to all species names is provided in Additional file 5: Table S2