This is the case in the stems of must Phanerogams and of some Pteridophytes.
De Bary's Comparative Anatomy of the Phanerogams and Ferns (1877) supplied an admirable presentation of the facts so far known.
Phanerogams or IV.
Ferns, horse-tails, club mosses, &c., and Phanerogams or Flowering Plants) the main plant-body, that which we speak of in ordinary language as the plant, is called the sporophyte because it bears the asexual reproductive cells or spores.
A considerable evolution in complexity can be traced in passing from the simplest forms of xylem and phloem found in the primary vascular tissues both among Pteridophytes and Phanerogams to these highly differentiated types.