Class
Subclass
Order
Classification
Subordinate Taxa
Nomenclature
Scientific Name:
Psilotum Sw., J. Bot. (Schrader) 1800(2): 109 (1801)
Synonymy:
- = Bernhardia Willd. ex Bernh., J. Bot. (Schrader) 1800(2): 132 (1801)
Type Taxon:
Etymology:
Vernacular Name(s):
fork fern
Description
Epiphytic or terrestrial ferns. Rhizomes dichotomously branched, subterranean, bearing brown rhizoidal hairs. Aerial stems erect or pendulous, dichotomously branched, angular or complanate (not NZ), glabrous. Sterile leaves small, scale-like, spirally arranged, lacking veins. Synangia trilobed, rounded, arranged adaxially on bifid, scale-like sporophylls. Spores monolete, ellipsoidal, rugulate to smooth.
Taxonomy
Psilotum is clearly distinguished from Tmesipteris by its highly reduced, scale-like leaves, and by the sporangia fused into trilobed synangia. At least 20 species and many varieties have been proposed (Reed 1966), but only two are accepted today (Chinnock 1998).
Distribution
A genus of two species widely distributed in the tropics and subtropics. One species indigenous in New Zealand.
Biostatus
Indigenous (Non-endemic)
| Category | Number |
|---|---|
| Indigenous (Non-endemic) | 1 |
| Total | 1 |
Cytology
Diploid to octoploid chromosome numbers of n = 52, 104 and c. 210 have been reported in specimens of Psilotum from different parts of the world, as well as possible triploid hybrids with 2n = c. 156 (see Brownsey & Lovis 1987).
Bibliography
Bernhardi, J.J. 1801: Tentamen alterum filices in genera redigenda. Journal für die Botanik (Schrader) 1800(2): 121–136.
Brownsey, P.J.; Lovis, J.D. 1987: Chromosome numbers for the New Zealand species of Psilotum and Tmesipteris, and the phylogenetic relationships of the Psilotales. New Zealand Journal of Botany 25(3): 439–454.
Brownsey, P.J.; Perrie, L.R. 2015: Psilotaceae. In: Breitwieser, I; Heenan, P.B.; Wilton, A.D. (ed.) Flora of New Zealand — Ferns and Lycophytes. Fascicle 9. Manaaki Whenua Press, Lincoln.
Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand ferns and allied plants. Edition 2. David Bateman, Auckland.
Chinnock, R.J. 1998: Psilotaceae. In: Flora of Australia. Vol. 48. 47–53.
Christenhusz, M.J.M.; Zhang, X.-C.; Schneider, H. 2011: A linear sequence of extant families and genera of lycophytes and ferns. Phytotaxa 19: 7–54.
Kramer, K.U.; Green, P.S. 1990: Pteridophytes and gymnosperms. Kubitzki, K. (ed.) The Families and Genera of Vascular Plants. Vol. 1. Springer-Verlag, Berlin.
Large, M.F.; Braggins, J.E. 1991: Spore atlas of New Zealand ferns and fern allies. SIR Publishing, Wellington.
Reed, C.F. 1966: Index Psilotales. Boletim da Sociedade Broteriana 40: 71–96.
Swartz, O.P. 1801: Genera et species filicum ordine systematico redactarum. Journal für die Botanik (Schrader) 1800(2): 1–120.
