Dryopteris erythrosora Autumn fern

Epithet means "red sori."

Evergreen, 2 to 3 ft. (60 to 90 cm). Zones (5) 6 to 9.Apogamous. description: The rhizome is short-creeping and produces

Dryopteris dilatata 'Lepidota Cristata'

a bountiful spring crop of remarkable red-stemmed and red-foliaged fronds. The frond is one-half stipe with an equal portion of broad, shiny, bipinnate, triangular blades with upwards of 10 pairs of pinnae. In time they fade from their coppery-red spring glory to a most acceptable glossy summer green, interrupted pleasantly on occasion by the arrival of a contrasting rosy autumn-colored new frond. The sori, of the botanical erythro (red), sora (sori), are indeed covered by bright red in-dusia, which yields to a traditional brown as the spores mature and depart.

range and habitat: A native of Japan, China, Korea and the philippines, autumn fern is common in their temperate forests.

culture and comments: This is THE species that inspired my interest in cultivation, propagation, and immersion in the wonderful world of ferns. (That was close to 40 years ago when, amazingly by today's market standards, it was unavailable commercially.) My admiration endures and I still hold it in my highest esteem for its universal adaptability and brilliant contribution to the garden's panorama. It is a top-10 recommendation for beginners and experts alike. once established, the plant is drought tolerant. The evergreen winter

Dryopteris dilatata 'Recurved Form' in the Kennar garden.

fronds remain cheerful and upright and put on a spectacular show when reaching above winter snows.

Autumn fern is variable, and specialty nurseries occasionally offer a number of equally attractive options. These include a dwarf form that has all of the appealing characteristics of the parent but matures at 18 in. (45 cm) at best.

'Brilliance' is a selection with especially bright, orange-

Structure Dryopteris
Ripe spores with their red characteristic on Dryopteris erythrosora.

toned, longer lasting color, and white to pale green rather than red indusia.

'Gracilis' (slender) is grown in Europe and is similar in structure to 'Prolifica' but without any inclination to produce bulbils. It does, however, come true from spores.

'Prolifica' is a finely cut, smaller version of the parent with propagable bulbils appearing sporadically along the rachis. The bulbils are more likely to be produced when the plant is slightly stressed (inducing survival?). To propagate simply and reliably, prick off the bulbils and incubate them in the comfort of a moist greenhouse enclosure or, as previously described, in pots capped with inverted clear plastic cups. Sporelings are consistently attractive, but not always bulbiferous.

'Prolifica Whirly Top' is a dwarf, 6- to 12-in. (15- to 30-cm) extremely congested sport which does bear bulbils.

Dryopteris expansa Northern wood fern, alpine buckler fern Synonyms Dryopteris assimilis, D. dilatata var. alpina Epithet means "expanded."

Deciduous, 11/2 to 21/2 ft. (45 to 75 cm). Zones 3 to 8.

description: The rhizome is erect, supporting upwardly tending sprays of fronds with one-third being grooved stipes. The scattered basal scales are brown with a darker stripe. The blade is broadly triangular-ovate, tripinnate-pinnatifid, and a pale, thin-textured green. There are 12 or more pairs of trian-

What Are Bulbils From Ferns
Coppery red "autumn" spring fronds on Dryopteris erythrosora in the Kennar garden.

gular pinnae with the lower pinnules on the lower pinnae "expanded" to twice the size of the corresponding upper pinnules. The characteristic is repeated in its offspring, Dryopteris campyloptera. The sori are medial and enclosed in a kidney-shaped indusium.

range and habitat: The northern wood fern has a strong preference for moist acidic soils and grows throughout the north temperate areas of North America, Europe, and Asia.

culture and comments: This species, along with Dryopteris intermedia, is a parent of D. campyloptera and is difficult, at best, to distinguish in the field where their range overlaps. (Flora of North America [1993] recommends counting chromosomes.) It is also challenging to the patience of the casual observer to differentiate it from D. dilatata with the latter being tripinnate rather than tripinnate-pinnatifid at the base. It is an easy garden plant for moist cool climates but does not do well in warmer areas, wilting even when well watered. Although deciduous, the fronds persist well into the frost season. I have always dismissed it as acceptable woodland filler until I met the stunning, black-stemmed Norwegian cultivar (and Scandinavia's only endemic) D. expansavar. willeanain several German gardens. Here is a showpiece ready to be prominently displayed among the best of the best. Like the type the leafage is airy but a chartreuse green perched in elegant contrast on shining black stems that in turn are decorated with pale brown scales.

A comparison of Dryopteris erythrosora 'Prolifica' wth its typical skeletal form (left) and D. erythrosora with its substantial contours (right).

The select Dryopteris erythrosora 'Brilliance'.
The native woodlander Dryopteris expansa in a coastal Washington habitat.
Dryopteris filix-mas in Pennsylvania.
Dryopteris filix-mas 'Barnesii' gives a ruffled show.
Ornate foliage of Dryopteris filix-mas 'Crispa Cristata' in the Schieber garden.

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