White meconella (Meconella oregana) COSEWIC assessment and status report: chapter 6
Biology
Life cycle and reproduction
Meconella oregana blooms in March to early April throughout its range and the blooming period is highly weather dependent (Rush et al. 1999; California Native Plant Society 2003; NatureServe 2003; Washington Natural Heritage Program 2004, writer’s observations 2004). Known populations can be very difficult to find in some years and very abundant in other years (Janszen pers. comm. 2004) in part because this annual species is very difficult to locate when not in bloom.
Location on record | Collector(s) and Year | Herbarium Records | Notes | Field- checked in 2004 (or why not checked) | Population in 2004 | Land and Protection Status | Size of population (or subpo- pulation) |
---|---|---|---|---|---|---|---|
Mt. Douglas (=Cedar Hill) | Macoun, 1875, 1876, 1884, 1887; C.F. Newcombe, 1916; Redfern, 1925; Hardy, 1945, 1952 |
CMN (1975, 1976, 1887) all on same herbarium sheet; RBCM (1916, 1925, 1945, 1952) | 1916: “small colony” |
x
|
not found | Regional Park | |
“Victoria” 1 | Dawson, 1876; Macoun, 1908 |
CMN (1876, 1908) | (exact location unknown)1 | not found | mostly private | ||
DepartureBay, Jesse Island | Spread borough, 1910 | CMN (1910) | (privately owned island) | not examined | private | ||
“Tod Inlet, Victoria” | Hardy, 1927 | RBCM (1927) | (exact location unknown) | not found | various | ||
Little Saanich Mtn., Saanich | C.F. Newcombe, 1917, 1928, 1931; Hardy, 1931; Ceska, 1977, 1980; Roemer, 2001, 2003 |
RBCM (1917, 1928, 1931a, 1931b, 1977) | 1917: “single plant” 2003: “ one of two subpopulations, approx. 20 individuals on 2 sqm” |
x
|
extant | Federal portion |
150
|
Private portion |
302
|
||||||
“Elk Lake” | Henson, 1933 | UBC (1933) | (exact location unknown) | not found | various | ||
Mt. Finlayson, Victoria | Carter, 1918; Hardy, 1925, 1936 | RBCM (1918, 1925); UBC (1936) |
x
|
not found | Provincial Park | ||
Thetis Lake Park, Victoria | Clark, 1958; Melburn, 1958, 1961 | UVIC (1958a); RBCM (1958b) |
x
|
extant | Regional Park |
368
|
|
Saturna Island | Janszen, 1974, 1987 | RBCM (1974) | 1987?: “lots of plants; only found in one small area” |
x
|
extant | private |
52
|
Nanoose Hill | Ceska, 1976, 1993; Douglas, 1976; Schofield, 1976 |
RBCM (1976a, 1976b); UBC (1976) | 1976: “ two small populations (~10 plants?)” |
x
|
not found | Federal property | |
Jocelyn Hill, Highlands District | Ceska, 1977, 1986; Roemer, 1997 |
RBCM (1977, 1997) |
x
|
not found | Provincial Park | ||
Galiano Island, Sutil Mtn. | Janszen, 1980 | RBCM (1980) |
x
|
not found | Galiano Conservancy and private | ||
Mt. Tzuhalem Ecological Reserve | William Newcombe, 1928; Ceska, 1980 |
(Observations?) |
x
|
not found | Provincial Ecological Reserve | ||
NE of Port Alberni | VanDieren, 1993a; Ceska, 1993b |
RBCM (1993a) | 1993b: “several thousand plants” |
x
|
extant | private |
1274
|
Skirt Mountain South | Ceska & Roemer, 2000, 2003 | 2003: “300+30 reproductive individuals” |
x
|
extant | private |
1209
|
|
Total: 15 Locations |
11/15
|
5 extant popns. | confirmed number 3355 |
2806 unprotected on private land; 151 unprotected on federal land; 368 protected in Regional Park
1 For place names in “quotes”, the exact locations are unknown because the locality descriptions are too inclusive and may overlap with other, more accurately pinpointed locations. In the intervening 70 or more years since these records were made the locations also have been subject to urban or at least residential development.
Localities (all surveys by writer, except where otherwise indicated in date column) | Survey dates mm/dd (all 2004) | Number of Meconella plants (highest total if visited repeatedly) | |
---|---|---|---|
Known localities where species was found in the past | Mt. Douglas, Saanich Municipality | 03/28, 04/07 | |
Known localities where species was found in the past | Little Saanich Mtn., Saanich Municipality | 03/11, 03/13, 03/19, 03/26, 03/29, 04/06, 04/09 |
422
|
Known localities where species was found in the past | Mt. Finlayson, Langford Municipality | 04/18 | |
Known localities where species was found in the past | Thetis Lake Park, View Royal Municipality | 03/23, 03/30, 04/01 |
368
|
Known localities where species was found in the past | Saturna Island | 03/22 04/05 (H.Janszen) |
52
|
Known localities where species was found in the past | Nanoose Hill | 03/16 | |
Known localities where species was found in the past | Jocelyn Hill, Highlands District | 03/27, 04/19 | |
Known localities where species was found in the past | Sutil Mtn., Galiano Island | 03/24 | |
Known localities where species was found in the past | Mt. Tzuhalem Ecological Reserve, Duncan | 04/02 (A. & O.Ceska) | |
Known localities where species was found in the past | NE of Port Alberni | 04/02 |
1274
|
Known localities where species was found in the past | Skirt Mountain South, Langford Municipality | 03/12, 03/13 |
1209
|
Unknown or lost localities where species was found in the past; too poorly defined | “Victoria”: Exact locality unknown; overlaps with several of the surveyed localities | ||
Unknown or lost localities where species was found in the past; too poorly defined | “Tod Inlet”: “Victoria”: Exact locality unknown; promising natural habitats are developed | ||
Unknown or lost localities where species was found in the past; too poorly defined | “Elk Lake”: Exact locality unknown; overlaps with two of the surveyed localities | ||
Known locality, not visited | Departure Bay, Jesse Island: (privately owned island) | ||
Additional localities with promising habitats | Bear Hill, Saanich Municipality | 03/(18?) | |
Additional localities with promising habitats | Skirt Mountain West, Langford Municipality | 03/17, 03/21 | |
Additional localities with promising habitats | Mill Hill, Langford Municipality | 03/20, 04/12, + many later visits | |
Additional localities with promising habitats | Mathews Point, Galiano Island | 03/24 | |
Additional localities with promising habitats | Stewart Mtn., Highlands District | 03/23 | |
Additional localities with promising habitats | Lone Tree Hill, Highlands District | 03/27 | |
Total |
3355
|
Very little information is known about the reproductive biology of Meconella oregana. Platystemon californicus, a closely related annual species from California is highly self-incompatible and has a high pollen:ovule ratio (Hannan, 1981). Although solitary bees pollinate P. californicus(Andrenidae and Halictidae), the plants are also wind pollinated (Hannan, 1981). Although Meconella oregana has a low number of stamens and fairly small stigmas, the high density of the plants may allow effective wind pollination (Hannan, pers. comm. 2004) especially since few pollinators are active in the early spring when it blooms. Although Meconella oregana is probably partially self-compatible, the stigmas expand above the anthers a day or two after anthesis to increase the potential for outcrossing (Ernst 1967). The petals close at night, which excludes the possibility of night pollinators (Ernst 1967).
In greenhouse experiments at Stanford University, Ernst (1967) found Meconella species difficult to grow: seedlings were susceptible to damping off and often required more than one year to germinate. Adding gravel to the top of pots helped aerate the base of the plants and prevented seeds from washing away (Ernst 1967). In Victoria Meconella oregana has in two instances been observed to germinate in the fall (Pinder-Moss, pers. comm. 2004, Hans Roemer's observations 2004/2005); however, at Stanford, it was observed to germinate in the spring. In natural habitats germination was found to begin after a wet/warm spell in late January (Hans Roemer's observation 2005).
Meconella oregana is an annual and the plant dies after producing seed. The seed may have a limited life expectancy because old seed does not germinate readily (Pinder-Moss, pers. comm. 2004).
Herbivory
Herbivores affecting Meconella oregana are not listed in any published literature and no signs of herbivory were observed in the field in 2004. The specific function of protopine and the additional alkaloid found in the closely related Meconella californica is not known. However, in other species, alkaloids are known to deter pathogens including bacteria, fungi, insects, nematodes and protozoa (Salmore and Hunter 2001). Alkaloids may also deter other herbivores.
Physiology
There is no literature on the physiological requirements and tolerances of Meconella oregana. The closely related Meconella californicahas been found to contain the alkaloid protopine in addition to a second minor alkaloid that could not be re-extracted in sufficient quantity for identification (Stermitz and Coomes 1969). In conditions of water stress, the closely related species, Platystemon californicus, was found to have decreased water potential, lower stomatal conductance and decreased photosynthesis. Platystemon californicusis not particularly sensitive to increased ozone levels (Bytnerowicz et al. 1988).
Dispersal
Meconella oregana produces many-seeded capsules that dehisce apically by three valvelike carpels. The carpels separate at maturity and occasionally twist (Gunn and Seldin 1976; Gunn 1980) releasing the seed. Although seed of other genera in the Papaveraceae have arils that attract ants as seed dispersers, Meconella oregana seed does not have arils (Ernst 1962; Gunn and Seldin 1976; Gunn 1980). Because of the small size of this plant, the small seeds (compare morphological description) and the lack of arils, dispersal distance from the parent plant is probably very limited. This is borne out by the very small areas occupied by the Canadian subpopulations. The average patch size of all 17 subpopulations found in 2004 was 3.4 m². However, it ranged as low as 0.03 m² (Figure 4). The fact that several subpopulations were found straddling deer trails suggests that longer-distance dispersal may occur with clumps of moist soil on the hooves of these animals (Hans Roemer's observations 2004).
Figure 4. Fifty Meconella plants at the Port Albernisite marked for counting. Note shallow soil and bike tracks.
Interspecific interactions
Fire may have played a role in maintaining habitat for Meconella oregana. Regular fires would have decreased competition by reducing shrub invasion and decreasing the growth of grasses and forbs (Rush et al. 1999; Washington Natural Heritage Program 2004). Populations of Meconella oregana are probably negatively impacted by competition from exotic annual grasses (Ertter pers. comm. 2004; Washington Natural Heritage Program 2004), which are very effective at capturing spring moisture. In the Canadian habitats, 25 non-native plants were among the associates of Meconella, seven of them exotic annual and biennial grass species.
Adaptability
As would be expected for an annual, the size of Meconella oregana plants and flowers changes in response to variations in seasonal rainfall and temperature (Ernst 1967). In 2004 the writer observed flowering specimens between 1 and 8 cm tall which ranged from single-stemmed to branched with up to five stems. Open flowers ranged from 2 to 6 mm in diameter. The largest plants occurred in less exposed and more sheltered, or in partly shaded microhabitats. Meconella plants were also observed to have their flowering period shorter and earlier in dry habitats and longer and later in seepage areas.
Page details
- Date modified: