Acrosorus

Acrosorus
Pressed specimens of Acrosorus streptophyllus
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Order:	Polypodiales
Suborder:	Polypodiineae
Family:	Polypodiaceae
Subfamily:	Grammitidoideae
Genus:	Acrosorus Copel.[1]
Type species
Acrosorus exaltatus (Copel.) Copel.[2]
Species
See text.

Acrosorus is a genus of ferns in the family Polypodiaceae, subfamily Grammitidoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I).^[2] It is known from the Philippines, Malesia, Thailand, and the Pacific islands.

Description

Members of the genus have radially symmetric (rather than flattened) rhizomes, covered with hairless scales of uniform color.^[3]

Their leaves may be partly cut, into lobes, or fully divided into pinnae. Their veins are at most a few times forked, and lack hydathodes.^[3] Each lobe or pinna of a fertile leaf bears a single sorus near the tip;^[4] the edges of the lobes or pinnae are rolled under and fused near the tip to protect the sorus.^[3][4] Leaf hairs may be single setae (bristles), single catenate hairs (consisting of chains of cells), or branched catenate hairs, with setae for branches.^[3]

Taxonomy

The genus was created by Edwin Copeland in 1906, to accommodate a group of ferns similar to Prosaptia and until then classified in Davallia.^[4]

Species

As of May 2024^[update], the Checklist of Ferns and Lycophytes of the World accepted the following species:^[1]

• Acrosorus friderici-et-pauli (Christ) Copel.
• Acrosorus pectinatus Parris ined.
• Acrosorus reineckei (Christ) Copel.
• Acrosorus schlechteri Christ
• Acrosorus sclerophyllus (Alderw.) Parris
• Acrosorus streptophyllus (Baker) Copel.
• Acrosorus subtriangularis (Alderw.) Parris
• Acrosorus tenuis Parris ined.
• Acrosorus vallatus Parris ined.

References

1. Hassler, Michael (18 May 2024), "Acrosorus", World Ferns. Synonymic Checklist and Distribution of Ferns and Lycophytes of the World, 19.3, retrieved 2024-05-19
2. PPG I (2016). "A community-derived classification for extant lycophytes and ferns". Journal of Systematics and Evolution. 54 (6): 563–603. doi:10.1111/jse.12229. S2CID 39980610.
3. Parris, Barbara S (2018). "The Flora Malesiana account of grammitid ferns (Polypdiaceae): a progress report with an illustrated synoptic key to Malesian genera". Sibbaldia (16): 25–27. doi:10.24823/Sibbaldia.2018.245. S2CID 134350895.
4. Copeland, Edwin (1906). "New Philippine Ferns". Philippine Journal of Science. 1 (supp. 2): 158.