BOTN 201 - Department of Biology Herbarium - TAMU
Images of the Navasota Flora - 6 August 1995
'Savannah' or open, grassy areas of the local Pistillate flowers of Phoradendron tomentosum (Viscaceae), are slowly maturing. A epiphytic (growing on another plant) and parasitic (extracts photosynthate from another plant). The latter is accomplished by the production of haustoria (evidently adventitious roots in Phoradendron) that penetrate woody tissue (xylem) of the host (many taxa, but often Quercus, Ulmus, and Celtis in our flora) and connect to the photosynthate conductive tissue (phloem). It is also the only angiosperm in our flora that is not - technically - a seed plant. An ovule is not formed within the Phoradendron gynoecium. The megagametophytes (2) differentiate within a specialized placental structure. There are no integuments, no 'seed coat', and - as a result - no seed.
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Last updated by HDW on 21 August 1995