Classification
Class
Polypodiopsida
Subclass
Polypodiidae
Order
Polypodiales Link
Family
Dryopteridaceae Herter
Genus
Dryopteris Adans.
 Nomenclature
Scientific Name:
Dryopteris stewartii Fraser-Jenk., Kalikasan 7: 272 (1979)
Synonymy:
Holotype: Pakistan, Hazara, Abbottabad District, 0.5 km N. of Changla Gali, Murree to Abbottabad, C.R. Fraser-Jenkins 6295, 25 July 1977, BM (n.v.; see Fraser-Jenkins et al. 2018)
Etymology:
Named in honour of Dr Ralph Randles Stewart (1890–1993), an American-born botanist who taught and studied plants in Pakistan for over 50 years. He is considered the father of systematic botany in Pakistan, and had a specialist interest in ferns.
 Recognition

Dryopteris stewartii has an erect rhizome and 2-pinnate, ovate laminae, which are yellow-green in colour. The stipe scales are narrowly ovate and dark brown. The laminae are ± glabrous adaxially, with very scattered tiny flat scales abaxially. The secondary pinnae are adnate or sessile on the primary pinna costae, and deeply toothed on their margins. They decrease in size to the primary pinna apices. The sori are arranged in one row either side of the costae, protected by reniform indusia (Hoshizaki & Moran 2001).

 Distribution

North Island: Northland.

Altitudinal range: c. 10 m.

Collected once as a garden escape in Kerikeri.

Occurs naturally in Afghanistan, Nepal, Pakistan and India (Fraser-Jenkins et al. 2018).

Dryopteris stewartii distribution map based on databased records at AK, CHR & WELT. Image: K.Boardman © Landcare Research 2020 CC BY 4.0
Dryopteris stewartii distribution map based on databased records at AK, CHR & WELT. Image: K.Boardman © Landcare Research 2020 CC BY 4.0
 Habitat

Recorded as self-sown in the nest leaves of ×Aglaonaria robertsii near cultivated parent plant.

 Biostatus
Exotic
 First Record

Heenan et al. (2008). Voucher AK 299450, 2006.

 Images
Dryopteris stewartii. Herbarium specimen showing the frond base of a self-sown plant from Kerikeri, AK 299450. Image: Auckland Museum © Auckland Museum All rights reserved
Dryopteris stewartii. Herbarium specimen showing the frond base of a self-sown plant from Kerikeri, AK 299450. Image: Auckland Museum © Auckland Museum All rights reserved
 Bibliography
Brownsey, P.J.; Perrie, L.R. 2021: Dryopteridaceae. In: Breitwieser, I. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 31. Manaaki Whenua Press, Lincoln.
Fraser-Jenkins, C.R. 1979: Dryopteris stewartii, a new fern from the West Himalayas. Kalikasan 7: 269–274.
Fraser-Jenkins, C.R.; Gandhi, K.N.; Kholia, B.S. 2018: An annotated checklist of Indian pteriodphytes. Part 2. Woodsiaceae to Dryopteridaceae. Bishen Singh Mahendra Pal Singh, Dehra Dun, India.
Heenan, P.B.; de Lange, P.J.; Cameron, E.K.; Parris, B.S. 2008: Checklist of dicotyledons, gymnosperms, and pteridophytes naturalised or casual in New Zealand: additional records 2004–06. New Zealand Journal of Botany 46: 257–283.
Hoshizaki, B.J.; Moran, R.C. 2001: Fern Grower’s Manual. Timber Press, Portland, Oregon.