The retention times of 10 oligosaccharides, generated from the xyloglucans of Rosa and Tropaeolum by the action of Trichoderma cellulase, and of 17 related carbohydrates, in h.p.l.c. on an amino-substituted silica (Amino-Spheri-5) depended largely on the number of hydroxyl groups per molecule, whereas h.p.l.c. on a pellicular anion-exchange resin (CarboPac PA1) was strongly influenced by the nature of the sugar residues present, especially l-fucose, and by their linkages. The major nonasaccharide (XG9, d-Glc4-d-Xyl3-d-Gal-l-Fuc) obtained from Rosa xyloglucan, after purification on Amino-Spheri-5, retained biological activity as an inhibitor of auxin-induced growth in a Pisum stem-segment bioassay. H.p.l.c. on Amino-Spheri-5 was used to monitor the action of "Driselase" in stripping the non-reducing terminal α-d-Xylp-(1→6)-β-d-Glcp units from XG9 to yield a pentasaccharide (XG5, d-Glc2-d-Xyl-d-Gal-l-Fuc).