Australian Tropical Ferns and Lycophytes - Online edition

Alsophila exilis


Click/tap on images to enlarge
Close up of frond showing sori. © G. Sankowsky
Close up of frond showing sori. © CSIRO
Frond. © G. Sankowsky
Crozier. © G. Sankowsky
Stipe scales. © CSIRO
Family

Cyatheaceae

Botanical name

 Alsophila exilis (Holttum) Lehnert

Link to Australian Plant Name Index for publication details and synonyms: https://id.biodiversity.org.au/name/apni/51350865

Description

Rhizome erect to 4 m tall, 4–8 cm diam., suckering from rhizome buds, with 1 bud near each stipe base. Stipe c. 20 cm long; stipe towards base with 0.5–1.5 mm long blunt spines, each spine bearing a caducous dull brown scale; scales c. 10 mm long and 1 mm wide; base thickened; margins fragile, sometimes setiferous; apex setose. Lamina to 100 cm long, thin; longest pinnae to 30 cm long; basal pinnae to 18 cm long; pinna rachis smooth, a few very narrow scales basally; pinnules to 5.2 cm long, 1.5 cm wide, deeply lobed; lobes at an angle of c. 60°, crenate, acute; veins to 7 pairs, those on fertile pinnules mostly forked; scales near bases of pinnule costae ovate; larger scales brownish, apically setiferous; smaller scales pallid, not setiferous; distal scales and those on costules small, bullate, sometimes with filiform apices; upper surface of costae bearing rather sparse antrorsely curved slender brown hairs. Sori medial, near the forks of veins; exindusiate, with few very small scales around receptacle; paraphyses longer than sporangia, distally flexuous, thickened at their bases. 

Distribution

Endemic to Australia and known from only one locality on CYP.

Habit and habitat

Terrestrial in spring-fed creeks in rainforest.

Natural history

This is a rare and localised endemic tree-fern.

Similar species

Similar to Sphaeropteris felinaIt is also very similar to Alsophila macgillivrayi from Papua New Guinea and the Louisiade Archipelago. Alsophila exilis is distinguished by its shorter stipe (c. 20 cm long cf. to 1 m in Sphaeropteris felina) and distinctly reduced basal pinnae ( cf. only slightly reduced in Sphaeropteris felina).

Citation of Australian Tropical Ferns and Lycophytes

Field AR, Quinn CJ, Zich FA (2022) Australian Tropical Ferns and Lycophytes. apps.lucidcentral.org/fern/text/intro/index.htm (accessed online INSERT DATE).

Field AR, Quinn CJ, Zich FA (2022) ‘Platycerium superbum’, in Australian Tropical Ferns and Lycophytes. apps.lucidcentral.org/fern/text/entities/platycerium_superbum.htm (accessed online INSERT DATE).

Copyright © Australian Tropical Herbarium 2022, all rights reserved.