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Polypodiaceae

Incl. Drynariaceae, Platyceriaceae

Mostly epiphytic ferns, sometimes terrestrial or rupestral; rhizome mostly creeping, sometimes scandent, bearing peltate-based, often clathrate scales, dictyostelic. Fronds mostly long-stipitate, mostly articulate to the rhizome, vascular bundles several to numerous in a simple ring, lamina simple, pinnatifid or pinnate (rarely digitately lobed), sometimes the lobes articulate to the rhizome, glabrous, sometimes hairy, or with stellate hairs or scales, veins mostly anastomosing with included free veinlets. Sori exindusiate, round or elliptical, sometimes elongate and linear, sometimes on contracted lobes or portions of lamina, sometimes spreading over large surfaces of the lamina and contracted or not (acrostichoid); annulus longitudinal, interrupted; spores monolete rarely trilete.

Distribution

A large, mostly tropical family of c. 50 - 60 genera and perhaps more than 1000 species. In Papuasia there are c. 20 genera with more than 150 species.

Literature

Van Alderwerelt van Rosenburg, C.R.W.K. 1918. Two critical fern genera: Angiopteris Hoffman; Lecanopteris Blume. Bull. Jard. Bot. Buit. ser. 2, 28: 57 - 64.

Copeland, E.B. 1912. The genus Thayeria. Philip. J. Sci. Bot. 7: 41 - 45.

Copeland, E.B. 1928. Leptochilus and genera confused with it. Philip. J. Sci. 37: 333 - 416.

Copeland, E.B. 1929. Papuan pteridophytes collected for the Arnold arboretum by L.J. Brass. J. Arn. Arbor 10: 174 - 182. (includes key to Pyrrosia as Cyclophorus).

Donk, M.A. 1954. Notes on Malesian ferns, I. On the genus Lemmaphyllum Presl. Reinwardtia 2: 403 -210.

Hennipman, E. & Roos, M.C. 1982. A monograph of the fern genus Platycerium. North Holland Publ. Co.

Hoshizaki, B.J. 1972. Morphology and phylogeny of Platycerium species. Biotropica 4: 93 - 117.

Joe, B.J. 1964. A review of the species of Platycerium, Polypodiaceae. Baileya 12: 69 - 126.

Pichi Sermolli, R.E.G. 1973. Fragmenta pteridologiae - IV. Webbia 28: 445 - 477. (incl. Goniophlebium, Phymatosorus, Phymatopteris).

Posthumus, O. 1927. Dipteris novoguineensis, ein "lebendes Fossil". Rec. Trav. Bot. Neerl. 25: 244 - 249.

Price, M.G. 1974. Nine new fern names. Kalikasan 3: 173 - 178. (Drymoglossum = Pyrrosia).

Roos, M.C. 1985. Phylogenetic systematics of the Drynarioideae (Polypodiaceae). Universiteitdrukkerij, Utrecht.

Genera

1a.

Fronds bearing stellate hairs

2

Fronds glabrous or bearing sparse simple hairs

4

2a.

Fronds simple and entire; sporangia in discrete, round sori or in elongate coenosori parallel to the midrib

3

Fronds dimorphous, some bracket-like and clasping the substrate, others dichotomously branched; sporangia acrostichoid, completely covering part of the surface of the fertile frond

Platycerium (2)

3a.

Sori continuous and elongate along the margins of a strongly narrowed and often elongate fertile frond, or between the margin and the midrib

Drymoglossum (c. 4)

Sori discrete and round, surrounded by stellate hairs, sometimes very close, but never continuous, the fertile portions of the frond not, or only very slightly, narrowed

Pyrrosia (c. 12)

4a.

Young sori protected by umbrella-shaped paraphyses with dark cross-walls; (sometimes difficult to see, in which case both branches of the key will work)

5

Young sori not protected by such paraphyses

8

5a.

Sori elongate, +/- acrostichoid, on a +/- narrowed apical portion of the frond

6

Sori separate, round or slightly elongate, between the midrib and margin, the fertile tip of the frond sometimes slightly narrowed

7

6a.

Fronds thick and leathery, venation indistinct or obscured in both fresh and dried material; transition to acrostichoid apical sorus abrupt, often with a constriction at the junction with the sterile lamina

Belvisia (c. 5)

Fronds thin and flexible, venation clearly evident in both fresh and dried material; transition to the sorus gradual, not constricted, the sorus elongate along the margin

Lemmaphyllum (1)

7a.

Large ferns with a stout rhizome, forming +/- "bird's nest" clump; sorus large, slightly elongate and parallel to the edge of the lamina, along the length of the frond, near the margin

Paragramma (1)

Small ferns, with long wiry rhizome climbing along thin branchlets; sori small, round, on the +/- contracted apical portion of the frond

Lemmaphyllum (1)

8a.

Sori at the ends of free excurrent veins, all free and/or included veinlets simple, excurrent

9

Sori not at the ends of free veins, including veinlets mostly branched, pointing in all directions

10

9a.

All veins free

Thylacopteris (1)

Some veins anastomosing

Goniophlebium (c. 5)

10a.

Rhizome inflated, hollow and ant-inhabited

Lecanopteris (3)

Rhizome solid, not ant-inhabited

11

11a.

Fertile fronds or fertile parts acrostichoid, with sori completely covering the lower surface, usually much contracted as compared with the sterile

12

Fertile fronds or lobes not acrostichoid, not strongly contracted, discrete sori present, elongate or not

17

12a.

Fronds pinnatifid, the lobes articulate to the rachis and falling off in old fronds, the lower lobes always sterile (Aglaomorpha)

Merinthosorus (2)

Fronds simple, fertile fronds fully fertile or fertile at the apex only

13

13a.

Fertile fronds fully contracted and fertile

14

Fertile fronds +/- contracted and fertile at the apex only

16

14a.

Fronds thin, all veins visible, margins entire

Leptochilus (1)

Fronds coriaceous, at most main veins visible, margins with small, distinct, regular notches

15

15a.

Sterile fronds narrow

Oleandropsis (1)

Sterile fronds broadly lanceolate

Grammatopteridium (? 1)

16a.

Fronds thick and leathery, venation indistinct or obscured in both fresh and dried material; transition to acrostichoid apical sorus abrupt, often with a constriction at the junction with the sterile lamina

Belvisia (c. 5)

Fronds thin and flexible, venation clearly evident in both fresh and dried material; transition to the sorus gradual, not constricted, the sorus elongate along the margin

Lemmaphyllum (1)

17a.

Fronds pinnate or pinnatifid, the pinnae or segments jointed to the rachis, falling off in old fronds

18

Fronds simple or pinnatifid, or pinnate, the segments not jointed to the rachis

25

18a.

Separate short, dry, humus-collecting fronds present, foliage fronds not humus-collecting at the base

Drynaria (3)

Separate humus collecting fronds absent, foliage fronds sometimes expanded and humus collecting at the base (Aglaomorpha)

19

19a.

Bases of fronds broad and humus-collecting

20

Bases of fronds not expanded and humus collecting

23

20a.

Fertile apical portion of frond strongly contracted and acrostichoid with a +/- continuous linear sorus

Merinthosorus (2)

Fertile portions, if contracted, with obvious visible lamina and several to many regular discrete sori

21

21a.

Fronds on special branches of the rhizome

Thayeria (? 1)

Fronds not on special branches, arising directly from the rhizome

22

22a.

Sori small, scattered, the fertile lobes broad, not contracted as compared with the sterile lobes

Drynariopsis (1)

Sori large, in a single row either side of the midrib of the strongly narrowed apical pinnae

Dryostachyum (1)

23a.

When fertile, apical lobes strongly contracted with +/- continuous linear acrostichoid sori

Merinthosorus (2)

Fertile lobes with discrete sori and obvious lamina

24

24a.

Fronds dimorphous, fertile fronds entirely fertile and contracted as compared with sterile, lamina noticeably hairy

Holostachyum (1)

Only the fertile pinnae narrowed as compared with the sterile, never the whole frond fertile

Aglaomorpha (1)

25a.

Fronds pinnate; sori small and round in a single row either side of the costa; lamina with large white hydathodes on the upper surface

Phymatopteris (1)

Fronds simple or pinnatifid; sori small to large, round to elongate, solitary between the main lateral veins or in 1-2 rows

26

26a.

Sori very elongate, oblique and parallel to the main lateral veins, or parallel to the costa

27

Sori round, elliptic or oval, or slightly elongate with 1 or more rows between the main lateral veins

29

27a.

Rhizome fleshy, mostly compact or short-creeping; lamina fleshy, without obvious lateral veins; spores trilete, rarely monolete

Loxogramme (c. 6)

Rhizome woody or wiry, mostly long- or short-creeping; lamina chartaceous or coriaceous, with obvious lateral veins; spores monolete

28

28a.

Fronds thin, all veins visible; margins entire

Colysis (1)

Fronds coriaceous, at most main veins visible; margins with small, distinct, regular notches

Selliguea (c. 20)

29a.

Fronds very narrow, not dimorphous; sori +/- elongate in a groove close to the costa

Holcosorus (? 1-2)

At least the sterile fronds broad, sori round, or elliptic or oval, between the main lateral veins

30

30a.

Rhizome scales opaque; lamina stiff and leathery, margin with small, distinct, regular notches

31

Rhizome scales +/- clathrate; lamina sometimes thin and soft, the margin entire without regular notches

Microsorium (c. 40)

31a.

Sori large, solitary or in a single row between the main lateral veins

Selliguea (c. 20)

Sori small, in pairs or in 2 rows between the main lateral veins

Crypsinus (c. 10)

Note

The genera Dipteris (Dipteridaceae) and Cheiropleuria (Cheiropleuriaceae) are sometimes included in the Polypodiaceae, but they are anomalous here with their bristly rhizomes.

Some authors remove the general Drymoglossum, Pyrrosia and Platyrcerium to a separate family, the Platyceriaceae. Others remove only Platycerium.

The genera Pyrrosia and Drymoglossum are closely related and some authors (e.g. Price 1974) consider that they should be united.

Similarly, Selliguea, Crypsinus, Phymatosorus, Oleandropsis and related genera have morphological boundaries that are not well defined and are considered congeneric to a greater or lesser degree by some authors.

There is confusion over the application of the name Lemmaphyllum. There are 2 species in this complex in Papuasia; the one with the linear apical sori may represent another (possibly an undescribed genus)and the one with the small discrete sori has been described as a separate genus and given the name Weatherbya or Lepidogrammitis.

Pichi Sermolli 1973) lectotypified Goniophlebium by an American species. If this view is accepted, the Old World species must be placed in another genus if they are considered distinct from Polypodium; Schellolepis is the earliest available name for this purpose.

Lecanopteris is maintained here as a "genus of convenience". It is considered by some to have evolved from 2 or more separate sources. Some authors prefer to recognise this according to the following key:

1a.

Rhizome glabrous, forming a series of hollow bulbs; fronds pinnatifid; sori on distinct small lobes of the ultimate segments

Lecanopteris (1)

Rhizome distinctly scaly, either sparsely or densely, forming a crust or a hollow tube; fronds simple or pinnatifid; sori not on small lobes, borne in a single row mid way between the costa or midrib and the margin

2

2a.

Rhizome sparsely scaly, a large raised crust clasping the trunks of trees; fronds pinnatifid

Myrmecopteris (1)

Rhizome densely scaly, a narrow hollow tube, climbing up the trunks of trees; fronds simple

Microsorium (Phymatosorus) (1)

The genera Drynaria, Merinthosorus, Drynariopsis, Dryostachyum, Aglaomorpha, Thayeria and Holostachyum form a closely related natural grouping within the Polypodiaceae, and have been included in their own family, the Drynariaceae. The division between the genera is not always clear-cut and some authors (e.g. Roos 1985) feel that some or all of the genera should be combined. The following key separates the Papuasian Drynarioids into two broad genera:

1a.

Separate reduced and specialised basket fronds present, quickly becoming brown (sometimes absent in terrestrial forms); apex of frond aborted and the apical lamina asymmetric

Drynaria (3)

Specialised basket fronds lacking, although the frond base may be expanded and modified, but then persistently green; apex of frond with normal development, symmetric

Aglaomorpha (6)

The genera Selliguea, Crypsinus, Holcosorus, Oleandropsis, Grammatopteridium and to a lesser extent Phymatopteris are very closely related. It has been proposed that they be united in whole or in part under Selliguea or Crypsinus.

Many authors recognise Microsorium as being composed of 2 genera:

1a.

Sori large, in a single row either side of the costa, often sunken into the lamina

Phymatosorus

Sori small, scattered over the lamina surface

Microsorium

Loxogramme is aberrant in this family with its predominantly trilete spores and fleshy fronds and rhizome bearing very clathrate scales. It has been included in the Grammitidaceae, but it is aberrant there with its large clathrate scales, non-chlorophyllous spores and large coenosori. Because of this confusion it has been placed in its own family, the Loxogrammaceae, by some authors.


Updated November 1999 by Jim Croft (jim.croft@environment.gov.au)