Friday, June 21, 2013

Two Flat Sedges – Cyperus haspan and Cyperus odoratus

Cyperus odoratus - Fragrant Flatsedge
Cyperus odoratus.

Flat sedges, members of the genus Cyperus, are rarely grown even though 35 native species occur in Florida, along with an additional 19 non-native species. Flat sedges are mostly wetland plants found in moist pine flatwoods, bogs, marshes, swamps, and along the margins of streams, ponds, and lakes. They also occur in artificial impoundments and ditches. A few species occur in dry sandy areas, such as sand scrub. Some species, both native and non-native, are extremely weedy and perhaps this has given the whole genus a bad reputation. Their flowers are individually insignificant and come in various shades of green or brown; however, they are aggregated into often conspicuous, sometimes even attractive, inflorescences.

I am currently growing, as potted plants, two native flat sedges. The first, shown above, is Cyperus odoratus (fragrant flat sedge). It is a common weedy annual found nearly throughout Florida. The second, shown below, is Cyperus haspan (leafless flat sedge). It is unusual in that the leaf blades are usually reduced to an inconspicuous sheath and its culms appear to be leafless. It is a perennial species that, like Cyperus odoratus, is a common, rather weedy, sedge found nearly throughout Florida.

Cyperus haspan

Cyperus haspan - Leafless Flatsedge or Haspan Flatsedge
Cyperus haspan

Nearly all flat sedges are effortlessly grown so long as they are provided with moist soil and plenty of sunlight. Usually, their cultivation presents only two significant problems. Each plant is capable of producing hundreds or thousands of seeds, each one of which seems to readily germinate. And flat sedges are identified on the basis of minute, technical, recondite characters and are very difficult for most gardeners to identify. As a consequence, it is often difficult for non-botanists to know whether a given flat sedge is a native species or an introduced, non-native species.

Images and text © 2013 Rufino Osorio

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