''Panicum hillmanii'', commonly known as Hillmann's panicgrass, is a grass from genus ''

Panicum ''Panicum'' (panicgrass) is a large genus of about 450 species of grasses native throughout the tropical regions of the world, with a few species extending into the northern temperate zone. They are often large, annual or perennial grasses, growi ...

'' native to

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...

. It has been introduced to many other areas, notably including southern Australia where it became widespread, and several parts of Europe.

Description

''Panicum hillmannii'' is a perennial grass that resembles the related '' P. capillare'' (hairy panic) in habitat and appearance. It is distinguished by slightly stiffer

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

s, firmer foliage, the rachilla shortly developed between the upper and lower

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...

s, the sterile

floret This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

which has the palea developed; and larger darker fertile lemma (up to 2mm long) with a prominent crescent-shaped scar at its base.

Distribution and habitat

''Panicum hillmannii'' is native to

Southwest United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...

. It was introduced to Australia in the early 1900s, and has spread across

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

and

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

, sharing the habitat with related native witchgrass ('' P. effusum''). It was also introduced to Europe, and specimens have been found in France, Belgium, Austria and Germany, although it remains relatively rare there and confined to agricultural weed in maize fields and habitats such as roadsides. Like several other ''Panicum'' species (''P. capillare'' and ''P. effusum''), Hillman's panicgrass can become a

tumbleweed A tumbleweed is a structural part of the above-ground anatomy of a number of species of plants. It is a diaspore that, once mature and dry, detaches from its root or stem and rolls due to the force of the wind. In most such species, the tumble ...

under extremely dry conditions, and can become a nuisance in residential areas due to the accumulation of grass stalks. Dry tumbleweed poses a serious fire danger. The plant is potentially harmful for grazing livestock, as it contains

saponins Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed ...

causing liver damage in animals.

References

External links

* * {{Taxonbar, from=Q15520804 hillmanii Poales of Australia Flora of the Southwestern United States Flora of New South Wales Flora of Victoria (Australia) Flora of South Australia Flora of Tasmania Tumbleweeds