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    • Abstract: NativeFernPropagation inGlacier National Park’sNative Plant NurseryTa r a L u n aAvalanche Creek in Glacier National ParkT wenty-two species offerns grow in GlacierNational Park (Lesica1996) in a diverse range of habitats

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Native
Fern
Propagation in
Glacier National Park’s
Native Plant Nursery
Ta r a L u n a
Avalanche Creek in Glacier National Park
T wenty-two species of
ferns grow in Glacier
National Park (Lesica
1996) in a diverse range of habitats
including seeping alpine cliff faces,
xeric-like talus slides and boulder
Propagation by Spores
An understanding of the life cycle of
ferns is essential for successful fern
propagation in nurseries. Ferns have
2 life stages: the gametophyte and
the sporophyte, the latter being the
fields, moist wooded slopes, stream spore producing fern plant we are all
Abstract banks, and forests. Ferns are a familiar with (Figure 1). Sporangia
prevalent component of the under- are variously placed on the lower
Six species of native ferns have been story in a mature Thuja plicata/ surface of leaves and grow in clusters
propagated by spores and rhizome Oplopanax horridum habitat type known as sori. In many species, the
division in Glacier National Park’s (Pfister and others 1977) in the sori are covered by specialized
Native Plant Nursery. Beginning Avalanche Creek drainage of Glacier outgrowths of the leaf, the indusia,
with spores, plants are ready for the National Park. Proposed restoration which lift and shrivel when spores
field in 14 to 16 mo. Rhizome efforts in this drainage prompted are ripe. A specialized layer of cells
division is used for further increase Park staff to investigate fern propa- (the annulus) on the stalks of spores
of nursery stock. The life cycle of gation techniques. Ferns can be contracts and expands, disseminat-
ferns is also discussed. sexually propagated by spores or ing mature spores with a catapult- 5
asexually propagated by division. In like discharge (Figure 2).
S P R I N G
KEYWORDS: Adiantum, Athyrium,
Glacier National Park’s Native Plant Disseminated spores germinate
Dryopteris, Gymnocarpium, spore
Nursery, 6 species representing 4 upon contact with a suitably moist
propagation
genera in 2 fern families have been substrate. Spore germination results
2 0 0 0
NOMENCLATURE: Flora of North successfully propagated by spores in the gametophyte (Figure 2),
America (1993) and division. see Glacier Ferns on page 7
V O L U M E 1 • N U M B E R 1
Taxonomy of ferns in North America has been exten- south through California, Nevada, Oregon, Washington,
sively revised. The formerly recognized fern family Idaho, Montana, Wyoming, Utah, Colorado, and South
Polypodiaceae is Dakota.
Taxonomy and Distribution now divided
into 16 families. Northwestern lady fern (Athyrium filix-femina (L.)
of Species Grown Fern nomencla- Mertens var. cyclosorum)
ture, distin- Athyrium filix-femina is a circumboreal species with 4
at Glacier National Park guishing recognized North American varieties. The variety
morphological cyclosorum is distinguished from the other 3 varieties by
characters, and geographic distribution of species having pinnules that are deltate to oblanceolate, being
propagated at Glacier National Park are described below. nearly equilateral at the base. It grows in moist woods,
swamps, and stream banks from 10 to 1600 m (33 to
5250 ft) elevation, from Quebec westward across
Pteridaceae Reichenbach
Canada, Alaska, south to Washington, Oregon, Califor-
Western maidenhair fern (Adiantum aleuticum
nia, Montana, Idaho, and South Dakota.
(Ruprecht) Paris)
Formerly, the western maidenhair fern was treated as a Toothed wood fern (Dryopteris carthusiana (Villers)
variant of Adiantum pedatum L., but both species are H.P. Fuchs Bull.)
reproductively isolated from each other and differ in Dryopteris carthusiana is a circumboreal species that
several morphological characters (Paris and Windham grows in swampy woods, moist wooded slopes, stream
1988). Apices of leaf margins in A. pedatum L. have banks, from sea level to 1200 m (3940 ft) elevation. It
rounded, crenulate, or crenate-denticulate lobes (0.1 to 2 occurs in North America across Canada, the northeast-
mm long) that are shallowly separated. Segments at the ern and upper midwestern states, and in Washington,
middle of the divisions of blades are usually less than 3.2 Idaho, and northwestern Montana.
times as long as broad. Apices of the leaf margins in A.
aleuticum have sharply denticulate, angular lobes, and Male fern (Dryopteris filix-mas (L.) Schott, Gen. Fil.)
the lobes are separated by deep sinuses, 4 to 6 mm long. Dryopteris filix-mas grows in moist woods, stream banks,
Segments at the middle of the divisions of blades are and among boulder and talus of igneous rock in the
usually more than 3.2 times as long as broad. Therefore, Rocky Mountains, from 200 to 2500 m (655 to 8200 ft)
A. aleuticum is now recognized as a distinct species elevation. It is a circumboreal species that is native in
growing in a variety of habitats throughout its range, North America throughout the western states and across
from sea level coastal cliffs, through moist wooded Canada to Greenland, the upper Great Lakes region, and
ravines and forests, to subalpine boulder fields, up to the northeastern US.
3200 m (10,500 ft) elevation. It ranges from Newfound-
land, Quebec, British Columbia and Alberta, all of the Common oak fern (Gymnocarpium dryopteris (L.)
US west of the Rocky Mountains, Maine, Maryland, Newman)
Pennsylvania, Vermont, and in the state of Chihuahua, Gymnocarpium dryopteris is a fertile allotetraploid species
Mexico. This species is disjunct in wet rock fissures at that arose following hybridization of G. appalachianum
high elevations in the Intermountain and Rocky and G. disjunctum (Pryer and Huafler 1993). Its wide
Mountain states and in Mexico. distribution across North America has allowed for
secondary contact with both diploid parents, resulting in
sterile triploid plants that produce 2 types of spores: 1)
Dryopteridaceae Herter
malformed spores incapable of germination, and 2)
American alpine lady fern (Athyrium alpestre (Hoppe)
round, viable spores which germinate and plants can
Clairville var. americanum)
arise apogamously (Pryer and Britton 1983). Collection
Athyrium alpestre var. americanum differs from A. alpestre of spores from triploid populations requires careful
var. distentifolium L. of Europe in several morphological discernment between non-viable and viable spores.
characters. The leaves of americanum are more finely Gymnocarpium dryopteris is a circumboreal species that
dissected and pinnae are broader with larger basal grows from Alaska across Canada to Greenland, and
6
pinnules than distentifolium. Indusia are absent or very south to Washington, Oregon, Idaho, Montana,
rudimentary in the American variety. Athyrium alpestre Wyoming, South Dakota, Colorado, New Mexico, and
2 0 0 0
var. americanum grows from 600 to 3100 m (1970 to the upper Great Lakes and northeastern states. It grows
10,170 ft) elevation, on wet talus slides, rocky slopes and in coniferous forests, stream banks, and moist cliffs from
S P R I N G
alpine and subalpine meadows. It is native in all the sea level to 3000 m (9840 ft) elevation.
Canadian provinces from Quebec westward, Alaska, and
N AT I V E P L A N T S J O U R N A L
Figure 1 • Indusia and mature spores on the underside of a frond of Dryopteris filix-mas.
Glacier Ferns from page 5 2). The sporophyte completes the season. In Glacier National Park at
which begins development as a life cycle when it grows into a 1050 m (3450 ft) elevation, sporan-
small, pale green, algae-like chain of mature fern plant and produces gia reached maturity in mid to late
cells known as the germ filament. spores. August. Sporangia must be moni-
Development continues into a flat, tored with a hand lens on a regular
heart-shaped structure called the Spore Collection and basis. The entire frond is collected
prothallus (Figure 2). Slender Processing when indusia (if present) begin to
holdfasts, known as rhizoids, develop Field plants should be located in lift and spores appear fully mature
on the lower surface of the prothal- early summer and inspected for the and are the ripe color for that species
lus. Both reproductive structures, the presence of sporangia on the under (Table 1; Figure 1).
antheridium (male), and the surface of leaves. Spore maturation, Fronds are placed spore-bearing
archegonium (female), develop on much like seed maturation, is surface down on butcher paper or
the lower surface of the prothallus. variable depending on weather newspaper and are kept indoors
Antheridia usually appear before the conditions throughout the growing under warm and dry conditions (20
archegonia, mostly near the rhizoids.
Archegonia appear near the notch of
the prothallus. Water must be TABLE 1
present for the multiflagellate sperm Indusia characteristics and mature spore color
to swim from an antheridium to
Species Indusia Mature spore color
eggs in the archegonium. After
Adiantum aleuticum false indusia tan
fertilization, the young sporophyte Athyrium alpestre none tan
receives its nutrients from the Athyrium filix-femina flaplike, thin, translucent tan
gametophyte through a foot-like Dryopteris carthusiana horseshoe or kidney shaped black 7
Dryopteris filix-mas horseshoe or kidney shaped black
structure. Further development is
S P R I N G
Gymnocarpium dryopteris none dark brown to black
rapid, and once the sporophyte
achieves a level of photosynthesis
sufficient to maintain itself, the
2 0 0 0
gametophyte disintegrates (Figure
V O L U M E 1 • N U M B E R 1
to 25 °C [68 to 77 °F]) without air
movement for 7 to 10 d. Spores will Leaf of
appear as a fine dust on the paper sporophyte
and can be immediately sown or plant
stored in sealed containers for future
use. Under ideal storage conditions
at 0 °C (32 °F) and 10% humidity
in airtight sealed containers, spores
can remain viable for up to 5 y
Sori
(Foster 1984).
Rhizome
Spore Germination
Germinate spores using sterilized
propagation flats with drainage
holes. Any sterilized commercial
soilless growing mix composed of Young
sporophyte Sporangium
6:1:1 milled sphagnum peat
moss:perlite:vermiculite is an Spores (1N)
appropriate medium. Moisten the Rhizoids
medium thoroughly with distilled Roots of
water. Hand sow spores directly on sporophyte
the surface of the moist medium
Prothallus Shoot
evenly and seal with clear plastic to
maintain humidity and avoid fungal First leaf Prothallus
contamination. Flats should be Archegonia
placed under soft incandescent lights (female)
Foot
(60 watts) on a timer for 12 h
Sperm Cells Antheridia
photoperiod at room temperature Embryo (male)
Zygote Prothallus
(20 to 23 °C [68 to 73 °F]). Periodic
(underside)
watering of the flats using a spray
Rhizoids
bottle containing distilled water will
be necessary. Water should be
applied when the medium begins to Sporophyte Generation Gametophyte Generation
dry slightly on the surface. Flats
Figure 2 • Development of spores in the reproduction cycle of a fern. (Source: Hartmann and
should also be closely monitored for
others (1997). Reprinted by permission of Prentice-Hall Inc, Upper Saddle River, New Jersey.
any fungal contamination.
Spores germinate 10 to 20 d after
sowing. The thread-like germ years until the correct moisture Osmocote controlled release
filament can be seen with the aid of conditions exist for fertilization. The fertilizer (13N:13P2O5:13K2O; 8 to
a microscope. Generally, prothalli clear plastic is removed from the 9 mo release rate at 21 °C [70 °F])
become visible 20 d after sowing. tops of the flats when antheridia and Micromax fertilizer (12% S,
Prothalli continue to grow for up to have withered and disappeared, 0.1% B, 0.5% Cu, 12% Fe, 2.5%
10 wk before reproductive struc- usually 4 wk after their initial Mn, 0.05% Mo, 1% Zn) are added
tures, antheridia and archegonia, appearance. Flats are then trans- at a rate of 4 g and 2 g per 800-ml
become evident on the under surface ferred from under indoor lights to container, respectively (5 and 2.5
of the prothallus. Both structures the greenhouse. kg/m3 [8.4 and 4.2 lb/yd3]).
can be seen with a microscope when Continued growth occurs rapidly
sampling a few prothalli from a tray. Growth and Development of Plants under greenhouse conditions and
Once reproductive structures appear, Young fern plants (sporophytes) with plants can be moved to an outdoor
it is important to maintain a thin true leaves and a developing root shadehouse or a shaded location
8
film of water over the surface of the system appear approximately 5 mo after the last frost in spring. All 6
prothalli; heavy misting using after sowing the spores. Individual species are rhizomatous and roots
2 0 0 0
distilled water should be applied to plants that are 4 cm (1.5 in) tall with form a firm root plug in the
the sealed flats once or twice a day. at least 2 true leaves are transplanted containers by the end of the growing
S P R I N G
This is necessary for fertilization to into 590- or 800-ml (36- or 49-in3) season. Plants can be fall planted in
occur. However, unfertilized containers using Pro-Mix #1 early September. If they are to be
prothalli can continue to live for medium (3:1 peat moss:perlite). held over, plants must be potted up
N AT I V E P L A N T S J O U R N A L
TABLE 2
General propagation timeline of native ferns in Glacier National Park
Athyrium alpestre
Athyrium filix-femina
Dryopteris carthusiana
Dryopteris filix-mas
Gymnocarpium dryopteris Adiantum aleuticum
Collect spores Aug 20 to 28 Aug 25
Sow spores in propagation trays Aug 28 to Sep 1 Sep 15
Gametophytes appear in trays Sep 15 to 20 Nov 15
Appearance of reproductive structures and fertilization Dec 1 Jan
Sporophytes appear Jan 20 to Feb 20 Feb
Transplant into 800-ml pots Mar Late Mar
Continued growth in outdoor shadehouse May 25 to Oct 25 May 25 to Oct 25
Root tight—outplant if desired Sep 1 Sep 1
Overwinter in outdoor shadehouse Oct 25 to May 1 Oct 25 to May 1
Transplant overwintered stock into 3-l containers May 15 to Jun 1 May 15 to Jun 1
the following spring into 3-l (1-gal) lengths, and planted 3 to 4 cm (1.5
References
containers. Plants reach reproductive in) deep in a raised outdoor bed Flora of North America. 1993. Volume 2,
maturity 2 y after initial spore containing a coarse growing medium Pteridophytes and gymnosperms. New
germination. Although it takes 1 y (2:2:1:1 peat moss:sand:per- York (NY): Oxford University Press. 475
to reach sizable nursery stock, lite:vermiculite). Individual plants p.
Foster FG. 1984. Ferns to know and grow.
literally thousands of plants can be grow from the split rhizomes the
Portland (OR): Timber Press Inc. 244 p.
produced from a few propagation following year. Lesica P. 1996. Checklist of vascular plants of
trays. Glacier National Park. 2nd ed. West
Summary Glacier (MT): Glacier Natural History
Vegetative Propagation Using spores, ferns can be grown in Association. 56 p.
Hartmann HT, Kester DE, Davies FT Jr, Geneve
Because all 6 species are rhizoma- the greenhouse and outdoor nursery
RL. 1997. Plant propagation: principles
tous, they can be increased from and out planted on appropriate sites and practices. 6th ed. Englewood Cliffs
established nursery stock by division. in 14 to 16 mo. The basic steps in (NJ): Prentice-Hall Inc. 770 p.
Adiantum, Athyrium, and Dryopteris propagation include: 1) monitoring Paris CA, Windam MD. 1988. A biosyste-
have rhizomes that are relatively spore maturity in the field; 2) matic investigation of the Adiantum
pedatum complex in eastern North
thick and shortened in relation to collecting fronds with mature, viable
America. Systematic Botany 13:240–255.
length. Individual sections of the spores; 3) germinating spores on Pfister RD, Kovalchik BL, Arno SF, Presby RC.
rhizome with 1 non-dormant lateral moist media; 4) growing gameto- 1977. Forest habitat types of Montana.
bud are made using a sharp knife, phytes and providing conditions for Ogden (UT): USDA Forest Service,
one-third of the fronds are removed, fertilization; 5) growing sporophytes Intermountain Research Station. General
Technical Report INT-34. 174 p.
and the individual sections are to necessary size for outplanting; 6)
Pryer KM, Britton DM. 1983. Spore studies in
transplanted into containers. increasing nursery stock by rhizome the genus Gymnocarpium. Canadian
Gymnocarpium has very slender division the following year, if Journal of Botany 61:377–388.
rhizomes with long internodes. needed. This protocol has been Pryer KM, Haufler CH. 1993. Isozymic and
These rhizomes are divided essen- successful for 4 genera. chromosomal evidence for the Allotetra-
ploid origin of Gymnocarpium dryopteris
tially the same way as the other
(Dryopteridaceae). Systematic Botany
species; ensuring that each section 18:150–172.
has at least 1 non-dormant lateral
bud. Divisions are done in the Author Information
spring prior to or just after the
Tara Luna
appearance of the tightly coiled
Biological Technician
fronds (fiddleheads). Native Plant Nursery
Rhizome wounding has been Glacier National Park
9
done on Athyrium alpestre and Box 384
Athyrium filix-femina. Rhizomes West Glacier, MT 59936
S P R I N G
[email protected]
were split down the center axis with
a sharp knife, cut into 20-cm (8-in)
2 0 0 0
V O L U M E 1 • N U M B E R 1


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