ISSN 1188-603X

No. 417 November 12, 2009 Victoria, B.C.
Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2


From: Adolf & Oldriska Ceska, Helen Atthowe, James Mack, & John Wood e-mail: c/o

Figures 1 & 2:

The California Sword Fern, Polystichum californicum (D.C. Eat.) Diels, was first reported from British Columbia and Canada by Wagner (1979) based on the specimen that W.B. Anderson collected on Texada Island in August 1897. Until Wagner's 1979 revision of the genus Polystichum, W.B. Anderson's specimen (a small single frond) had been consistently misidentified as Polystichum scopulinum (D.C. Eat.) Maxon.* In August 2007, Terry Ludwar found a single plant of P. californicum on a rock wall in Maple Bay, north of Favada Point (Ceska et al. 2009). This plant had contorted leaves, probably as a result of the exposure to salt spray: and

During the summer of 2008, James Mack and John Wood discovered a new site of Polystichum californicum at the wall of rock cliffs at the southwestern base of Surprise Mountain on Texada Island. In October 2009, the authors visited this site and found altogether 18 plants of this species. This population consisted of healthy plants with several young plants scattered along the rock wall for approximately 90 m. This site is about 3 km ESE of the single plant in Maple Bay that was reported earlier in BEN.

Collection data:

Polystichum californicum (D.C. Eaton) Diels - Dryopteridaceae Canada, British Columbia: Texada Island, Van Anda municipality, limestone rock walls at SW slopes of Surprise Mtn. 49° 43.22´ N. 124° 35.89´ W. UTM 10U 384810 E 5508761 N (NAD 83) elev.100 m. In fissures of limestone rock (Quatsino Formation) at the contact with basalts of the Karmutsen Formation. With Rubus ursinus Cham. & Schlecht. and Poa marcida A.S. Hitchc. Collection date: October 11, 2009 Collectors: Adolf & Oldriska Ceska, Helen Atthowe, James Mack, & John Wood Coll. No.: A&OC # 35000 (UBC) [2 fronds] Identified: Adolf & Oldriska Ceska - October 2009 [Photo confirmed by D.H. Wagner]


Ceska A., O. Ceska, J. Dove, T. Ludwar, J. Mack, & D. H. Wagner. 2009.
Polystichum californicum (Dryopteridaceae) found again on Texada Island, British Columbia. BEN - Botanical Electronic News 402.
Wagner D. H. 1979.
Systematics of Polystichum in western North America north of Mexico. Pteridologia 1: 1-64.

*[Note: this species was originally published on 11/12/09 as Polystichum setigerum (K. Presl) K. Presl.; corrected on 12/6/09 by -AC]


From: Paul M. Catling & Gisèle Mitrow, Agriculture and Agri-Food Canada, Environmental Health, Biodiversity, Saunders Bldg., Central Experimental Farm, Ottawa, Ontario K1A 0C6 Canada []

The Phragmites database at the Global Biodiversity Information Facility Website has recently been accessed at a rate of more than 50 times a week.

It is possible to go directly to the 297 records of Phragmites australis (Cav.) Trin. ex Steud.subsp. australis by following:, or for 920 records of Phragmites australis subsp. americanus Saltonstall by following, or to see all Canadian Phragmites (1634 records of both subspecies including 417 plants not identified to subspecies) follow

Database Content:

The data are based on material that we have examined, verified and annotated in 20 herbarium collections and museums across Canada including ACAD, ALTA, CAN, DAO, MMMN, MT, MTMG, NSPM, QFA, QUE, SASK, TRT, TRTE, UBC, UNB, UPEI, UWO, V, WAT, and WIN (acronyms from Holmgren et al. 1990 and Holmgren 2005).

Identification criteria and misclassification:

Research, some of which is published (Robichaud and Catling 2003, Saltonstall et al. 2004, Catling 2006, Catling et al. 2007) has established that Phragmites australis subsp. americanus differs from subsp. australis in having shorter first glumes and that glume length is strongly correlated with colour of lower stem internodes. Older collections and those from native habitats consistently have red lower internodes suggesting that this is characteristic of the native subspecies (e.g. Catling et al. 2007). In preparing the database all specimens with clearly red or reddish-purple lower stem internodes were referred to subsp. americanus, whereas all specimens with yellow internodes were referred to subsp. australis. Specimens without bases, of which there are many because plant collectors frequently collect only the reproductive portion of these tall plants, were identified using the following method which is based on a bimodal distribution of maximum lower glume length correlated with stem colour.

Using specimens with bases showing stem internodes and identifying them according to internode colour, we found that using the lower glume limit of 4.3 mm, the misclassification rate is approximately 6.7%. However, other limits can be selected by assigning individuals in the overlap zone to the category of "unknowns" and this was done for identification of specimens in the database. All plants with lower glumes under 3.8 mm long were assigned to Phragmites australis subsp. australis, with the result that 0.3 % of subsp. americanus (identified on basis of stem colour) would be misidentified. Thus P. australis subsp. australis in the database is fairly reliably identified. All specimens with lower glumes over 4.2 mm long were assigned to subsp. americanus which would result in 6.6 % of plants possibly referable to subsp. australis being misclassified. However, these misclassification rates may be based on rare mutants lacking red pigment or to hybrids. This method resulted in 15.8 % of specimens with only inflorescences being unidentified (as a result of occupying the overlap zone).

About half of the plants in the database (approx. 850) are without basal stems so being able to identify the majority of these reliably using glume length is useful in providing much additional data. Being able to identify plants on the basis of glume lengths is also valuable in winter and spring when stem internodes are not available. Of course plants collected in autumn with lower stems and mature inflorescences are the best for identification. Internode colour appears to be the most important character but is not infallible (Catling et al. 2007) so that using other characters that nevertheless overlap somewhat is helpful in determining the reliability of an identification. The following key (Catling et al. 2007) appears to be the most reliable for identification of Canadian plants. For information on how these are distinguished from other species elsewhere in the world, see Catling (2007).

la. Lower stem internodes yellowish or yellowish-brown; lower glumes 2.6-4.2 (4.8) mm long; ligule of middle 
    leaf excluding fringe 0.1-0.4 mm high . . . . . . . . . . . . . . . . .  subsp. australis (introduced)

lb. Lower stem internodes reddish-purple; lower glumes 3.8-7.0 mm long; ligule of middle leaf excluding fringe 
    (0.2) 0.4-0.9 mm high  . . . . . . . . . . . . . . . . . . . . . . . . . . subsp.  americanus (native)


We appreciate the extensive help of Ms. Lynn Black with databasing. Derek Munroe and Guy Baillargeon assisted with making the database available through GBIF.

Literature Cited

Catling P. M. 2006.
Notes on the lectotypification of Phragmites berlandieri and identification of North American Phragmites. BEN - Botanical Electronic News 366.
Catling P.M. 2007.
Additional notes on the identification of alien Phragmites in Canada. BEN - Botanical Electronic News 370
Catling P.M., G. Mitrow & L. Black. 2007.
Analysis of stem color for grouping Phragmites taxa in eastern Ontario and an evaluation of lower glume length and ligule length for separating stem colour groups. Rhodora 109 (938): 125-136.
Holmgren P.K.. 2005.
Online database of the Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff.
Holmgren P.K., N.H. Holmgren & L.C. Barnett. 1990.
Index herbariorum. Part 1: The Herbaria of the World. The eighth edition. The New York Botanical Garden Press. 693 p.
Robichaud L. & P. M. Catling. 2003.
Potential value of glume length in differentiating native and alien races of Common Reed, Phragmites australis. BEN - Botanical Electronic News 310.
Saltonstall K., P. M. Peterson & R. J. Soreng. 2004.
Recognition of Phragmites australis (Poaceae): Arundinoideae) in North America: evidence from morphological and genetic analysis. Sida 21(2): 683- 692.


From: Gisèle Mitrow & Paul M. Catling, Agriculture and Agri-Food Canada, Environmental Health, Biodiversity, Saunders Bldg., Central Experimental Farm, Ottawa, Ontario K1A 0C6 Canada []

Using the NatureServe ranking system (Morse et al. 2004) Phragmites australis subsp. australis has been ranked as the top priority invasive alien plant in Canada (Catling 2005). Although there have been relatively few detailed studies of its impact on native biodiversity, the circumstantial evidence for a huge impact is very strong since the plant now occurs in many thousands of places previously occupied by a rich assemblage of native species. A few examples of observations and studies in eastern Canada indicate a very broad spectrum of impacts:

(1) St. Lawrence River wetlands: Of the invasive alien plants of wetlands of the St. Lawrence River in Quebec, Phragmites austratlis was found to be highly competitive and to have a greater impact on native plant biodiversity than any of the other invasives present including purple loosestrife (Lythrum salicaria L.. ). Studies of the impact of common reed on biodiversity in the St. Lawrence region of southern Quebec are ongoing.

(2) Long Point Biosphere Reserve on Lake Erie: This area contains some of the most important habitats for staging waterfowl in the Great Lakes. Naturally the loss of native wetland vegetation here is a great concern. In 2003 P. australis subsp. australis was expanding in this area at a rate of 50% per year (Meyer 2003). Based on a study of aerial photographs taken from 1945 to 1999, Wilcox et al. (2003) found that four kinds of vegetation had been extensively reduced by Phragmites australis subsp. australis (Typha marsh, marsh meadow, sedge/grass hummock, and mixed emergents). In a detailed study of impact on animals, Meyer (2003) found that the development of dense stands of P. australis subsp. australis reduced numbers of Swamp Sparrows, rails, waterfowl, Northern Leopard Frogs, and Fowler's Toads but benefitted Least Bitterns, Red-winged Blackbirds, warblers, meadow voles and shrews.

(3) Lake St. Clair marsh and wet prairie: Here P. australis subsp. australis is threatening the habitat of the endangered Eastern Prairie Fringed Orchid, Platanthera leucophaea (Nutt.) Lindl., and other rare native prairie plants. It appeared here in early 1990's. Following decline of the orchid, an invaded area was sprayed with glyphosate and later burnt resulting in effective control and dramatic growth of the rare native orchid. Without this decisive action, this population of an already threatened species would have probably been eliminated. There has been substantial loss of native marsh vegetation and particularly cattails to Phragmites australis subsp. australis over the last few decades and some useful methods of demonstrating decline have been developed on the basis of studies in the Lake St. Clair region (Arzandeh & Wang 2003, see also Pengra et al 2007).

(4) Fens: A number of fens in New York State have been taken over by Phragmites australis subsp. australis with the loss of all native vegetation (pers. obs.). It has taken over 27% of the open area of Bergen Swamp, one of the most biodiversity-rich wetlands in the state. Not surprisingly it is regarded as a threat to a large, attractive silk moth (Hemileuca sp.) that is very rare and confined to a few fens in New York State and Ontario: &

Fens are unusual on the landscape and contain many rare and restricted species. The loss of Ontario fens (Minesing, White Lake, Hayes Bay, Stoco, etc) to P. australis subsp. australis seems inevitable without intervention based on the situation in New York, and it would likely lead to the extirpation or serious endangerment of many species of plants and animals.

(5) Farmland in eastern Ontario and southwestern Quebec: Phragmites australis subsp. australis is invading cereal crops in parts of eastern Ontario and southern Quebec, in some cases reducing yield by up to 50% on parts of the cultivated land. Near St. Grégoire it has competed successfully with corn along field edges eliminating 3 rows of corn (specimens in DAO, P.M. Catling pers. obs.).

(6) St. Lawrence River estuary: Between 2003 and 2005 (Phragmites australis subsp. australis was observed expanding in the tidal marshes at Rivière du Loup and La Pocatière. It expanded through the upper marsh to the edge of the Spartina alterniflora Loisel. zone. Species displaced by the advancing stand comprised of P. australis subsp. australis alone included Agropyron spp., Carex spp, Chenopodium spp., Convolvulus sepium L. , Eleocharis spp., Festuca rubra L., Hierchloe odorata (L.) P. Beauv., Juncus balticus Willd., Potentilla anserina L., Scirpus spp., Solidago sempervirens L, Spartina patens (Aiton) Muhl. , and S. pectinata Link (specimens at DAO 804213, 791517, P.M. Catling, personal observation).

(7) Lake Huron shoreline: In a recent survey of Phragmites australis subsp. australis in this area, Bickerton (2007) found the plant to be in the early stages of invasion along a full 60 km of coastline. It was not present in this area during a survey of coastal vegetation in 1975 (pers. obs.) and is believed to have established beginning in 2002 based on discussions with residents. Alarmingly, in this area it is growing on sandy beaches and dunes, even with Dune Grass (Ammophila breviligulata Fern.). Replacement of many kinds of native vegetation was reported (Artemisia campestris L., Elymus canadensis L., Eupatorium spp., Scirpus spp. Typha spp.). Wasaga Beach Provincial Park has recently developed an action plan to deal with alien Phragmites which is considered a threat to the endangered Piping Plover, since the bird requires open sand, which is being replaced by dense stands of Phragmites australis subsp. australis.

Although there is no comprehensive list of the number of native North American species negatively impacted by Phragmites australis subsp. australis, it would probably be a substantial compilation (thousands). Despite this, there are some success stories and innovative controls. One of the more interesting is the use of grazing to control Phragmites in the habitat of the endangered Bog Turtle in North Carolina ( Others are the success of manual control by underwater cutting (Smith 2005) and a volunteer group saving an important fen in Massachussetts (Martin 2001). Although P. australis subsp. australis may have an extremely detrimental effect on biodiversity overall, it is to be expected that in some situations, it will benefit certain native species (see for example under Long Point above, and Rodriguez 2006).

Literature Cited

Arzandeh S. & Wang, J. 2003.
Monitoring the change of Phragmites distribution using satellite data. Canadian Journal of Remote Sensing 29: 24-35.
Bickerton H. 2007.
Occurrence of Common Reed (Phragmites australis) on Lake Huron shorelines: Field Report and Recommendations. Report prepared for the Lake Huron Centre for Coastal Conservation. 24 p.
Catling P.M. 2005.
New "top of the list" invasive plants of natural habitats in Canada. BEN - Botanical Electronic News 345:1-7.
Lavoie C., M. Jean, F. Delisle & G. Létourneau. 2003.
Exotic plant species of the St Lawrence River wetlands: a spatial and historical analysis. Journal of Biogeography 30: 537-549.
Martin T. 2001.
Success story, Phragmites control at Kampoosa Bog, Massachusetts. The Nature Conservancy.
Meyer S. 2003.
Comparative use of Phragmites australis and other habitats by birds, amphibians, and small mammals at Long Point, Ontario. M. Sc. Thesis, University of Western Ontario. PDF available at
Morse L. E., J. M. Randall, N. Benton, R. Hiebert & S. Lu. 2004.
An invasive species assessment protocol - evaluating non-native plants for their impact on biodiversity. Version 1. NatureServe, Arlington, Virginia.
Pengra B.W., Carol A. Johnston, & Thomas R. Loveland. 2007.
Mapping an invasive plant, Phragmites australis, in coastal wetlands using the EO-1 Hyperion hyperspectral sensor. Remote Sensing of Environment 108(1): 74-81.
Rodriguez L.F. 2006.
Can invasive species facilitate native species? Evidence of how, when, and why these impacts occur. Biological Invasions 8: 927-939.
Smith S.M. 2005.
Manual control of Phragmites australis in freshwater ponds of Cape Cod National Seashore, Massachusetts, USA. Journal of Aquatic Plant Management 43: 50-53.
Wilcox K.L. & S. Petrie. [sine dato]
Investigation and Long-Term Monitoring of Phragmites australis at Long Point, Lake Erie, Ontario.
Wilcox K.L., S.A. Petrie, L.A. Maynard & S.W. Meyer. 2003.
Historical distribution and abundance of Phragmites australis at Long Point, Lake Erie, Ontario. Journal of Great Lakes Research 29(4): 664-680.

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