landscapes. Simply defined, turfgrasses are flowering plants capable of producing uniform perennial ground cover due to their unique growth habit and there are few, if any, other species of plants that can play a similar role.
Research on the origin of widely used turfgrass species is shedding light on their time and location of development and adaptation. Te centers of origin of common turfgrass species vary and can be found all over the world. Many of the cool-season turfgrass species originated in Europe and Asia while warm-season grasses originated mostly in Africa, Asia, and North America.
Top Left: Inflorescence of the turfgrass St. Augustinegrass. Top Right: Inflorescence of the grain crop Sorghum. Bottom Left: Inflorescence of the grain crop Wheat. Bottom Right: Inflorescence of the ornamental grass Pampas Grass. Photos provided by Dr. Casey Reynolds
However, they still possess all of the same reproductive features as other flowering plants including a pistil (stigma, style, ovary) and stamen (anther, filament).
So why do so many people not think of them as flowering plants? First and foremost, turfgrasses do not produce showy, colorful flowers, which is what many people associate with the term flowering.
Reproductively speaking, they do not need these features to attract pollinators because they are self-pollinated. In grasses, these structures are compacted into miniature flowers called florets that are small and inconspicuous, so they often go unnoticed. Tese florets are arranged into larger structures called inflorescences, sometimes referred to as seedheads, and there is a wide range of diversity in inflorescences among grasses.
Interestingly, one turfgrass species with another level of diversity is buffalograss. While all other turfgrass species have perfect flowers, meaning that male and female reproductive features are found in the same flower, buffalograss is dioecious meaning that male (staminate) and female (pistillate) flowers are found on separate plants. While other landscape plants are selected specifically for the appearance and color of their flowers, turfgrass inflorescences are routinely removed through mowing. Turfgrasses have evolved through grazing such that their meristem, or growing point, remains at the soil surface allowing its leaves to be grazed or clipped without killing it. Tis is unlike any other flowering plant found in landscapes and is one of the most unique features of turfgrasses. It allows them to persist under mowing and traffic while forming a uniform ground cover that is functionally important to the success of many urban
TPI Turf News November/December 2017
For many years, turfgrass breeders throughout the world have taken advantage of this diversity by identifying and selecting successful, naturally occurring phenotypes and bringing them to market. Tey also have identified naturally occurring interspecific crosses as well as created new grasses through
modern plant breeding techniques. Tis is all in an effort to produce new turfgrasses that are better adapted to climate extremes, drought, traffic, pests, etc.
Te many benefits of perennial turfgrasses in urban centers have been well-documented with regard to— capturing rainfall, reducing stormflow, reducing erosion, protecting watersheds from soil and nutrient runoff, and filtering pollutants in urban runoff—due to their fibrous root system, high organic matter content, and diverse populations of soil micro-organisms.
Tey also are one of the most effective species of plants for remediating disturbed topsoil. Home and building construction practices often remove, destroy, or significantly impact the health of these systems and the high carbon sequestration rates and fibrous root systems of perennial grasses are one of the most effective ways of returning soil structure to a more natural state. In fact, the United States Environmental Protection Agency (US EPA), along with many state agencies, often list turfgrass sod in its recommendations for planting in areas that require topsoil remediation and/or erosion control.
Soil remediation is largely a result of carbon sequestration as plants capture atmospheric CO2
and deposit it below
ground in roots, stems, decomposing leaf tissues, etc. Tere are an estimated 40-50 million acres of urban grasslands in the United States alone which can sequester the annual emissions of up to 3.9 million cars. Recent research indicates that turfgrasses managed in urban settings are a net carbon sink for atmospheric CO2
even after accounting for maintenance emissions from mowing, fertilization, etc. 81
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