Botanists call grasses and other grass-like plants "graminoids". This diverse group of plants belongs to the taxonomic class called the monocots (Monocotyledoneae)– these are flowering plants (Angiosperms) that sprout a single seed-leaf when they germinate. The leaves of graminoids are generally long and linear in form and always exhibit a parallel pattern of venation. Monocots are one of the two primary classes of the flowering plants, along with the dicots (which sprout two seed leaves and have a "reticulate", or branching venation pattern).After the forbs, graminoids are the most species-rich growth-form type represented in the vascular plant flora of Denali. There are 174 species from five different plant families of graminoids known to occur in Denali National Park and Preserve. The sedge family contributes by far the largest number of species of any vascular plant family to the flora of Denali. Nearly 100 species of this family are known to occur in the park, including 79 species of the genus Carex (the sedges) which is the most species–rich genus we have. The other graminoid plant families represented in the park flora are as follows: Grass family (Poaceae; 56 species); Rush family (Juncaceae; 20 species); Arrowgrass family (Juncaginaceae; 2 species) and last but not least, the Cattail family (Typhaceae; 1 species).
Graminoid species are very well represented in Denali’s wetland flora. These plants often form the defining element of wetland plant communities – the familiar wet sedge meadow that lines the margins around ponds and in swampy openings within the boreal forest. Large, robust sedges such as Carex aquatilis, Carex utriculata, and Carex canescens are particularly plentiful in these wetland habitats.
The graminoids are a very ecologically diverse group of plants, however, and are by no means restricted to marshy and wet sites in Denali. In fact, a diverse set of these plants, including many of the grasses and sedges (species from the families Poaceae and Cyperaceae) are found in the driest plant communities on the landscape – communities occupying steep south-facing slopes from the lowlands all the way to dry alpine ridges.