Cystodium; It’s Not a Tree Fern: It’s a Polypod!

Jessica Zamiara

PBIO 209

Once Upon a Time….

• 1841 Cystodium Sorbifolium (J.Smith)

• Lowland (1300 ft) Malaysian Rainforests

Cystodium Sorbifolium

• Non Arborescent Tree Fern

• Why Dicksonia?

1965

• Two Papers Published

• The Gametophyte of Cystodium & New Cytological Records for Cystodium & Dicksonia

• Uniting factor lack of hairs on the Thallus of Dicksonia & Cystodium Gametophyte

• Cystodium 2n=112, n=56

1966

• Anatomy of Cystodium, Sen & Mittra

• First detailed account• Stark contradicts

between Dicksonia & Cystodium

• Differences do not rule out origin from a common ancestor

1981

• Spore Morphology in the Dicksoniaceae, Gastony

• 32 typical number for spores per sporangia - not apogamous!

• Completely different from other cyatheoid-dicksonioid species

1983

• B.S. Parris

• Conserve Cystodium against Cystodium Fee

1986

• The Stipe & Rachis Vasculature of the Dicksonioid Fern, Cytodium Sorbifolium. Croft

• Sen & Mittra had stipe wrong

• Genera Cystodium & Dicksonia have little in common other than hairy stipe & indusium structure

• Proposed through anatomical, spore, chromosome evidence for Cystodiaceae

2006

• On the Phylogenetic position of Cystodium, Korall et al.

• DNA sequence data from rbcL and atpB

• Cystodium is resolved into the polypod clade with high support

• Tentatively inclusion in Lindsaeceae, certainly not a member of Dicksoniaceae

Lived happily ever after….

BibliographyLenette R. Atkinson , 1965, The Gametophyte of Cystodium. American Fern Journal, Vol. 55,

No. 1, pp. 32-35 J. R. Croft, 1986,The Stipe and Rachis Vasculature of the Dicksonioid Fern, Cystodium

sorbifolium (Cystodiaceae). Kew Bulletin, Vol. 41, No. 4, pp. 789-803 Gerald J. Gastony, 1981, Spore Morphology in the Dicksoniaceae. I. The Genera Cystodium,

Thyrospteris, and Culcita. American Journal of Botany, Vol. 68, No. 6, pp. 808-819 Petra Korall, David S. Conant, Harald Schneider, Kunihiko Ueda, Harufumi Nishida, Kathleen

M. Pryer, 2006, On the Phylogenetic Position of Cystodium: It's Not a Tree Fern: It's a Polypod! American Fern Journal, Vol. 96, No. 2, pp. 45-53

B. S. Parris, 1983, Proposal to Conserve Cystodium J. Smith (Pteridophyta: Dicksoniaceae)

against Cystodium Fée (Fungi: Incertae sedis). Taxon, Vol. 32, No. 4, pp. 648-649 S. K. Roy and R. E. Holttum, 1965, New Cytological Records for Cystodium and Dicksonia. American Fern Journal, Vol. 55, No. 1, pp. 35-37 U. Sen and D. Mittra, 1966, The Anatomy of Cystodium. American Fern Journal, Vol. 56, No.

3, pp. 97-101