Difference between revisions of "Danthonia californica"
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| + | California oatgrass produces seed from both open flowers that allow for cross-pollination and closed flowers that have obligate self-pollination. Its open pollinated flowers are referred to as chasmogamous and the seed they produce are chasmogenes (chasmogamic seed). | ||
| + | Closed pollinated flowers are cleistogamous and the seed they produce are cleistogenes (cleistogamic seed). The chasmogamous seed is produced in the exposed panicle and is sometimes referred to as terminal seed. In contrast, the cleistogamous seed is primarily found at the lower nodes of the flowering culm and typically remains enclosed in the leaf sheaths (Dobrenz and Beetle 1966, Campbell et al. 1983). | ||
| + | Spikelets are flattened with 5-10 flowers (florets) each. Photo by Steve Matson used with permission. | ||
| + | There are differences between chasmogamic and cleistogamic seed production. Sometimes referred to as hidden seed, cleistogenes are typically shorter or longer (narrower) and larger than seed from the inflorescence and some lack a developed lemma and palea (Dobrenz and Beetle1966). Most commonly, there are 3-4 spikelets per flowering culm and 5-6 florets per spikelet. However, a single lower node can bear 6-7 cleistogenes and there can be 5-6 such nodes per culm. Therefore, more hidden seed can be produced than terminal seed. Production of cleistogenes increases under grazing pressure (Dobrenz and Beetle 1966). | ||
| + | Seed coat characteristics may also differ between the two seed types as evidenced by contrasting germination responses to acid scarification reported by Laude (1949). Bruns (2005) found that seed set was lower in chasmogamous spikelets compared to cleistogamous spikelets and more maternal reproductive effort was put into cleistogamous seed production. However, chasmogamous seed had higher and quicker germination rates, as well as a higher rate of early seedling growth compared to cleistogamous progeny. In contrast, Weatherwax (1928) states there are no consistent differences in the two types of caryopses (naked seeds) and that both types germinate alike and seedling plants are alike in appearance and vigor through flowering. | ||
| + | By July or August after the panicle has matured and some of the terminal seed has shattered (fallen from the plant), the remaining culm will disarticulate (separate) at the basal node (Darris pers. obs.). Dispersal of remaining cleistogenes is probably aided by this process (Dobrenz and Beetle 1966). The dry stems with enclosed seed may wrap around the feet or limbs of passing animals (Darris pers. obs.). | ||
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Revision as of 10:48, 30 April 2012
Contents
Danthonia Californica
Family: Poaceae, Synonyms: Danthonia Americana, California Oatgrass, four botanical varieties of Danthonia californica: var. americana, var. californica, var. palousensis, and var. piperi.
Taxonomy
Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Liliopsida – Monocotyledons
Subclass Commelinidae
Order Cyperales
Family Poaceae – Grass family
Genus Danthonia DC. – oatgrass
Species Danthonia californica Bol. – California oatgrass
Description
California wild oat grass is a low, perennial bunchgrass, to 1 1/2 ft. tall, with dense tufts of fuzzy, dull-green leaves and half-decumbent flowering culms with nodding spikelets. This grass is not particularly conspicuous even in flower.
California wild oat grass grows in moist, open sites; meadows, forest; above 6,500 feet.
Perennial, tufted grass from fibrous roots; stems disarticulating at the nodes (ten) 30-130 cm tall. Leaves: Sheaths smooth or soft hairy, the upper ones usually smooth or unevenly soft hairy, the hairs 1-2 mm; blades (one) 2-5 (6) mm wide, flat to in-rolled, smooth to soft hairy; ligules less than 1 mm long, fringed with fine hairs. Flowers: Inflorescence a raceme of (two) three to six (ten) slightly to broadly spreading spikelets, the branches longer than the spikelets; spikelets (ten) 14-26 (30) mm long; lemmas 5-10 mm long, hairy along the margins, rarely smooth, sometimes sparsely hairy over the back, the apical teeth stiff-awned, (2) 4-6 (7) mm long, also awned from the back, these awns abruptly bent, (7) 8-12 mm long, the calluses usually longer than wide, with stiff hairs laterally; anthers to 4 mm long (Douglas et al., 2001). Source: The Illustrated Flora of British Columbia
California oatgrass (family: Poaceae) is a slow establishing yet long lived, cool season (C3) perennial bunchgrass of intermediate texture. Its stems (culms) grow 30-100 (10-130) cm tall and disarticulate (separate) at the lower nodes (joints). The leaf sheaths are smooth to densely hairy. Leaves are both basal and attached to the stem with the upper blades being 8-25 (10-30) cm long, flat to in-rolled, and spreading to abruptly bent. The ligule (at the throat of the leaf blade) is less than 1 mm and fringed with small straight hairs. Additionally, 1-3 mm long, soft spreading hairs appear at the leaf collar and throat (photo). Flowering occurs in May or June depending on location. The panicle (inflorescence) is 2-6 cm long, loose, and open with 1-5 (3-6) broadly spreading spikelets. Glumes are 14-18 mm long. There are 3-8 (5-10) florets (flowers) per spikelet (see photo). Lemmas are 5-10 (8-15) mm long, hairy along the margins with stiff awned teeth and an abruptly bent awn that is (4) 8-12 mm long (Darbyshire 2003, Hickman 1993, Hitchcock et al. 1969, Klinkenberg 2007).
Bloom Period
California oatgrass produces seed from both open flowers that allow for cross-pollination and closed flowers that have obligate self-pollination. Its open pollinated flowers are referred to as chasmogamous and the seed they produce are chasmogenes (chasmogamic seed). Closed pollinated flowers are cleistogamous and the seed they produce are cleistogenes (cleistogamic seed). The chasmogamous seed is produced in the exposed panicle and is sometimes referred to as terminal seed. In contrast, the cleistogamous seed is primarily found at the lower nodes of the flowering culm and typically remains enclosed in the leaf sheaths (Dobrenz and Beetle 1966, Campbell et al. 1983). Spikelets are flattened with 5-10 flowers (florets) each. Photo by Steve Matson used with permission. There are differences between chasmogamic and cleistogamic seed production. Sometimes referred to as hidden seed, cleistogenes are typically shorter or longer (narrower) and larger than seed from the inflorescence and some lack a developed lemma and palea (Dobrenz and Beetle1966). Most commonly, there are 3-4 spikelets per flowering culm and 5-6 florets per spikelet. However, a single lower node can bear 6-7 cleistogenes and there can be 5-6 such nodes per culm. Therefore, more hidden seed can be produced than terminal seed. Production of cleistogenes increases under grazing pressure (Dobrenz and Beetle 1966). Seed coat characteristics may also differ between the two seed types as evidenced by contrasting germination responses to acid scarification reported by Laude (1949). Bruns (2005) found that seed set was lower in chasmogamous spikelets compared to cleistogamous spikelets and more maternal reproductive effort was put into cleistogamous seed production. However, chasmogamous seed had higher and quicker germination rates, as well as a higher rate of early seedling growth compared to cleistogamous progeny. In contrast, Weatherwax (1928) states there are no consistent differences in the two types of caryopses (naked seeds) and that both types germinate alike and seedling plants are alike in appearance and vigor through flowering. By July or August after the panicle has matured and some of the terminal seed has shattered (fallen from the plant), the remaining culm will disarticulate (separate) at the basal node (Darris pers. obs.). Dispersal of remaining cleistogenes is probably aided by this process (Dobrenz and Beetle 1966). The dry stems with enclosed seed may wrap around the feet or limbs of passing animals (Darris pers. obs.).
Distribution
Habitat
Uses
Native bunchgrasses like California oatgrass are valuable for enhancing biodiversity. Healthy stands can reduce invasion by exotic species yet exhibit a spatial distribution compatible with forbs (Maslovat 2001). Combined with other native grasses and forbs, California oatgrass improves habitat diversity for feeding, nesting, and hiding by songbirds (Oregon Department of Fish and Wildlife 2000), as well as other animals. The grains are eaten by small birds and mammals (Mohlenbrock 1992). Prairies with California oatgrass as a definitive species are also unique refuges for other endemic organisms. For example, the Ohlone tiger beetle (Cicindela ohlone) is an endangered (federally listed) predatory insect known only to five remnant stands of California native grassland in Santa Cruz County (Santa Cruz Public Libraries 2003). These rare grasslands, including the coastal terrace prairies, remain biodiversity “hotspots” and are considered in need of protection (Stromberg et al. 2001).
Forage: As a rangeland plant, California oatgrass is well utilized by livestock and certain wildlife. Prior to maturity, the species is rated as good to very good forage for cattle and horses in the Pacific Coast states, but less palatable for sheep and goats. Ratings are lower for eastern, drier portions of its natural range (USDA Forest Service 1988). Others claim it is palatable to all classes of livestock and a mainstay grass for range grazing in places like Humboldt County, California (Cooper 1960). California oatgrass withstands heavy grazing (USDA Forest Service 1988, Cooper 1960). However, it is also reported that animals seek out and overgraze individual plants sometimes leading to rapid stand depletion (Crampton 1974). This species can provide green forage year round in some areas. Under moderate grazing it stools readily, forms a “sod” (ie. the bunches coalesce), and can produce a substantial volume of high quality forage. Less desirable species diminish as the sod forms. Higher nutritional content and grazing preference make California oatgrass desirable in a management system over soft chess (Bromus mollis) (Heady et al. 1963). Protein analysis is high at 8 to 26 percent; the low point coming in January after the herbage has been leached by precipitation (Cooper 1960). This species has formed Plant Materials <http://plant-materials.nrcs.usda.gov/> Plant Fact Sheet/Guide Coordination Page <http://plant-materials.nrcs.usda.gov/intranet/pfs.html> National Plant Data Center <http://npdc.usda.gov> stands dense enough for haying in California (USDA Forest Service 1988).
Pollinators: California oatgrass is used as food by the caterpillar larva of certain butterflies including two skippers (Hesperia lindseyi and Hesperia columbia) (Robinson et al. 2007). It is an important component of native grasslands that form critical habitat for other butterflies including the vulnerable Vancouver ringlet (Choenonymphya tullia insulana), Taylor’s checkerspot (Euphydryas editha taylori) (Chappell 2006), and the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) (Collins 2006). Cover and turf: Other potential uses include cover and erosion control in vineyards, young orchards (Edminster 2003), grassy lanes, and parks, as well as along trails. As a candidate for native lawn, this species can be planted and mowed to maintain a turf- like stand in landscape settings or elsewhere (Wrysinski 2004, Daniels 2007, Amme 2003). California oatgrass persists along compacted hiking trails and takes heavy foot traffic, trampling, and moderate summer moisture stress. It also has potential as a stay-green firebreak (Edminster 2003, Fire Safe Council 2007).
Propagation
Photo Gallery
Seed
Abbreviation: DACA
Seed sample from: 2011
Average Measurement with husk/awn: 13.75 x 1.5 x 0.8
Measurement Range with husk/awn: L: 12 - 16, W: 1.2 - 1.9, D: 0.75 - 1
Average Measurement without husk/awn: 3.5 x 1.5 x 0.9
Measurement Range without husk/awn: L: 3.25 - 3.75, W: 1.3 - 1.75, D: 0.75 - 1.1
Features
Shape: Seed tapered at ends, hilum flared into two points.
Color: Seed light brown, husk cream colored.
Additional Features: Lemma sharply pointed and has several nerves. Palea rounded at top. Lemma fringed at inner edge with, white bristles and bearded at hilum. Awn cork screws once or twice and then straightens.
Surface: One seed face has a groove that runs longitudinally almost entire length of seed. The opposite seed face has a depression that forms an elliptical ridge. Seed is very finely textured with longitudinal lines and is slightly shiny.
Latitudinal Cross Section: elliptical 
Longitudinal Cross Section: elliptical 
Basic Explanations and Assumptions:
The dimensions for the seeds are length x width x depth. The location of the hilum is used as the base of the seed, and the length is measured from hilum to the opposite apex. Where a style is present, the length is measured from the hilum to the bottom of the style. Width is measured at a right angle to the length at the widest part. Depth is measured at a right angle to the intersection of height and width lines.
Measurements included are the mean average for each measurement of ten separate seeds.
All measurements in millimeters unless otherwise noted.
