Nassella pulchra (Hitchc.) Barkworth
C. Michael Hogan PhD
May 31, 2009
Nassella pulchra is widely distributed species throughout California grasslands, and is, in fact, the state grass; however, California grasslands represent a threatened ecosystem due to intensive conversion to agricultural land, urban development and invasion of non-native grasses. Correspondingly, N. pulchra is receiving strong consideration by researchers for grassland restoration. Seeds of N. pulchra were extensively used by prehistoric Native Americans as a food source. The scientific name derives from Latin, with Nassella meaning a diminutive narrow-necked basket, referring to the inflorescence shape; pulchra is the Latin for beautiful.
N. Pulchra is a perennial bunchgrass that attains a height of 30 to 100 cm. Roots of mature plants extend to an amazing depth of up to seven meters, allowing the notable longevity of individuals that may reach centuries in age. The deep rooting not only enables extended age of plants, but also the prehistoric dominance of the species throughout its range, which is generally arid. Leaf blades vary from 0.8 to 3.5 mm. (Jepson) The plan-view footprint of the plant is somewhat elliptical, with the long axis parallel to topographic contour lines of hillslopes; (Fehmi et al.) this characteristic is significant in that the species has above average erosion control due to the broader base of its downslope runoff interception in relation to its gross cover area.
The tough basal leaves remain green most of the year, while stems and inflorescences turn brown in April or May as the dry season commences. The common name is derived from the clearly purple seed heads, especially evident in early seed formation; furthermore, One flowered spikelets are covered with whitish hairs, (Stubbendieck et al.) and inflorescences have a nodding habit.The panicles have a translucent silvery appearance, particularly after the initial early season purple hue subsides and the plant is backlit. Seeds have extended awns resembling a thread attached to see needle shaped seed. The awn ranges from 38 to 100 mm, and is severely twice-bent accentuating the "thread" appearance; distil segment of the awn is straight. Plants are dormant in the summer and resume growth in the autumn.
DISTRIBUTION AND HABITAT
Purple Needlegrass occurs in grasslands, chaparral and oak woodland in California extending south to Baja Mexico at elevations less than 1300 meters.. Within California it is found in Northwestern California, northern and central Sierra Nevada Foothills, southern Sacramento Valley, Central Western California, South Coast, Channel Islands, Western Transverse Ranges, western Peninsular Ranges. Prehistorically it was thought to be the dominant grass in California. (Heady et al.) In a climax prehistoric native N. pulchra dominant grassland, individual plants would be spaced significantly apart, reflecting the survival of deeply rooted older members.
On Northern California coastal prairies significant native grass associates are Elymus glaucus, Danthonia californica, Dechampsia caespitosa, Festuca idahoensis and Koeleria macrantha. Representative dicot forbs in that ecosystem include: Lupinus bicolor, L. variicolor, Lotus formosissimus, L. micranthus, Microseris acuminata, Cirsium quercetorum, Anaphalis margaritacea, Daucus pusillus, Heracleum lanatum, Plantago erecta, Eriogonum latifolium, Fragaria vesca and Viola adunca. Example native coastal prairie (non-grass) monocot associates include: Carex tumulicola, C. subbracteata, Sisyrinchium bellum, Juncus occidentalis, J. patens, J. bolanderi, J. capitatus, Luzula comosa, Calochortus tolmiei and Triteleia laxa. The coastal prairie geometry may be represented by a rounded hillform such as the Estero Americano of Sonoma County, or alternatively by a coastal terrace landform.
The ecosystem of an open forest oak woodland or savanna provides somewhat different associates with an overstory of Quercus agrifolia, Q. douglasii, Q. garryana and Q. kelloggii.(Hogan) Example understory associates in open grassland patches are: Cynoglossum officinale, Cardamine californica, Wyethia helenioides, Mimulus aurantiacus, Dichelostemma congestum, Calochortus amabilis, Calochortus luteus, Rubus ursinus, Calochortus amabilis, Lithophragma affine, Calystegia purpurata and Pellaea andromedifolia.
In the Central Valley's Yolo Wildlife Area, representative grassland associates include: Eryngium vaseyi, Asclepias fascicularis, Achyrachaena mollis, Apocynum cannabinum, Hesperevax caulescens, Lasthenia fremontii, L. glaberrima, Psilocarphus oregonus, Aster chilensis, Lepidium nitidum, L. oxycarpum, Cress truxillensis, Cyperus eragrostis, Lotus wranglianus, Trifolium fucatum, Trifolium microdon, Juncus mexicanus, Pogogyne douglasii, Ranunculus canus, Myosurus minimus, Triteleia hycinthina, Calandrinia ciliata, Castilleja attenata and Epilobium pygmaeum. Poaceae family associates include: Alopecurus saccatus, Hordeum brachyantherum, H. depressum, Glyceria occidentalis, Phalaris lemmonii and Poa secunda.
N. pulchra was designated as California's state grass based upon its broad distribution, role as a Native American food and significance as an anchor to California's grassland ecology; its designation was facilitated by support from the California Native Grass Association and California Native Plant Society. California grasslands are ranked in the top ten endangered ecosystems in the USA. Such grasslands encompass approximately 10,000,000 hectares, seventy percent of which have been heavily invaded by non-native grasses. (Angelo) Nassella pulchra offers substantial advantages as a species for grassland restoration, not only because of its prehistoric dominance, but also due to its erosion control capability and its ability to out-compete invasive species such as Starthistle. Non-native grasses such as Holcus lanatus, Bromus diandrus, Dachtylus glomerata, Vulpia bromoides, Lolium perenne and Poa annua are other invasive species which diminish the native ecology of grasslands on which N. pulcra is a prominent species.
To understand the ongoing damage of Star Thistle as one invader, one must visualize that over 6,000,000 hectares of grassland in California are infested with this noxious weed; the principal expansion of this invader occurred in the first half of the 20th century due to intensive non native grazing, although original introduction of the weed occurred about 1849 as an impurity of alfalfa seed imported from Chile, after Chilean import from Spain. Based upon published values (Ditomaso et al.) of pasture productivity change upon Starthistle invasion, I have calculated an annual cost to California agriculture as approximately $300 million per annum, assuming full herbicide control, or $100 million per annum based upon uncontrolled Starthistle and absorbing grazing productivity loss. Successful restoration projects have been conducted in California using both plugs and seeding, (Buisson et al.) with only moderate impacts being realized from native herbivores (e.g deer, rabbits, gophers)
Early studies of grassland restoration began in California in the 1950s, but lack of adequate controls in many studies have resulted in more new questions being posed rather than answered; N. pulchra has been a mainstay of analysis for a preponderance of the studies. N. pulchra has been shown to be more resilient to controlled burning than the majority of natives and non-natives. Grazing has been stimulant to be an effective stimulant to native forb and grass diversity, but only when the seasonality is targeted to minimize seed dispersal from exotics. Significant research and restoration projects involving California grasslands have been carried out recently at Elkhorn Slough, Carmel Valley and the Estero Americano, the latter owned by the Sonoma Land Trust.
* Jepson Manual. 1993. Nassella pulchra: Purple Needle Grass, University of California Press, Berkeley, California
* James L. Stubbendieck, Stephan L. Hatch, L. M. Landholt, Kelly L. Rhodes Hays. 2003. North American wildland plants: a field guide, University of Nebraska Press, 501 pages ISBN 0803243065
* Jeffrey S. Fehmi, Michelle Hammond and James W. Bartolome. 2008. Alignment of Elongated Nassella pulchra Plants with Hill-Slope Contours, Arid Land Research and Management, 22:212-215, Taylor and Francis
* H.F. Heady, J.W. Bartolome, M.D, Pitt, G.D. Savelle and M.C. Stroud. 1992. Coastal Prairie in R.T. Coupland ed. Natural grasslands: introduction and western hemisphere, Elsevier, New York, pp 313-332
*.K.J.R. Morghan and K.J. Rice, Centaurea solstitialis invasion success is influenced by Nassella pulchra size, Restoration Ecology, Blackwell Publishing
* Sean Anderson, Karen D. Holl, Emmanuel Corcket, Grey F. Hayes, Alain Peeters, and Thierry Dutoit. 2008. Reintroduction of Nassella pulchra to California coastal grasslands: Effects of topsoil removal, plant neighbour removal and grazing, Applied Vegetation Science 11(2):195-204.
* C.Michael Hogan. 2008. Blue Oak: Quercus kelloggii, GlobalTwitcher.com, ed. N. Stromberg http://www.globaltwitcher.com/artspec_information.asp?thingid=85046〈=us
* Courtney Angelo. 2005. Restoration of Danthonia californica, Elymus glaucus, and Nassella pulchra at Elkhorn Slough National Estuarine Reserve, Department of Ecology and Evolution, University of California, Santa Cruz
* Joseph M. Ditomaso, Guy B. Kyser and Michael J. Pitcairn. 2006. Yellow Starthistle Management Guide, California Invasive Plant Council, Berkeley, California