Fig. S2.

Hypertrophy induced by parasitic plants. (A) Tomato plants, Solanum lycopersicum (Sl), were infected with Phtheirospermum (Pj) and surveyed for morphological changes at haustorium attachment sites (HA). Pictures show an unstained (Left) and Safranin-O stained (Right) infected root at 30 dpi. (B) Safranin-O–stained sections of Phtheirospermum haustoria on tomato root with xylem bridges (XB) at 30 dpi. (C and D) Hypertrophy on crabapple trees, Malus toringoides (Mt), induced by European mistletoe, Viscum album (Va). Photographs were taken at Cambridge University Botanic Garden, Cambridge, United Kingdom (October 22, 2016). (Scale bars: A, 0.5 mm; B, 100 µm.)