comprises trees (including conifers), club mosses, horsetails, ferns, cycads, flowering herbs, grasses, and all shrubs.
Kingdom: Plantae Division: Tracheophyta
Class: angiospermopsida Order: Rosales Family: Leguminosae Genus: Gleditsia Species: triacanthos Forma: (none for this particular plant) Variety: inermis Cultivar: "Sunburst"
A theory which encompasses a consideration of all vascular plants, and which is based primarily upon studies of the lower Tracheophyta
, recent and fossil, has had greater vitality--so much so, indeed, that it has permeated the thinking of many morphologists and paleobotanists to a degree not realized by those who have not followed the literature in these fields.
Apparent restriction of CAM to the Tracheophyta may be explained in part by the greater carbon allocation to cell wall material in these macrophytes, resulting in C acquisition being a more rate-limiting step than N, P, or Fe acquisition (Raven & Spicer, 1995).
Being restricted to the Tracheophyta means that CAM is found only in secondarily aquatic plants.