|Heide-Jørgensen H S, Kuijt J. 1995. The haustorium of the root parasite Triphysaria (Scrophulariaceae), with special reference to xylem bridge ultrastructure. Amer. J. Bot. 82: 782-797.|
|Figure legend for the diagram shown to the left:
Semidiagrammatic sketch of mature haustorium of Triphysaria having a xylem bridge with a single xylem strand. Upper Fig. Three-dimensional diagram of diarch parasite root having only primary structures and pentarch host root. The plate xylem (PX) includes parenchyma cells (no internal structures shown) and tracheary elements. Lower Fig. Transverse section of parasite and host root. The primary xylem is diarch. Opposite the haustorium the cortex consists of three cell layers including exodermis. G is part of the plate xylem.
Abbreviations: E, epidermis. EN, endodermis. G, graniferous tracheary element of plate xylem. H, host root. HX, host xylem element. IP, interface parenchyma cell. IW, lignified interface cell wall. PC, pericycle. PH, phloem. PX, plate xylem. S, exodermis. SX, secondary xylem. T, trichome. X, interface xylem element. XB, Vessel member of single-stranded xylem bridge.