Selliguea

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Selliguea

Description

Epiphytic, epilithic or terrestrial, small to medium-sized ferns.

Distribution

Asia-Tropical: Australasia:, Queensland (Queenslandpresent) From India to Japan: present Pacific:, Fiji (Fijipresent)
From India to Japan, throughout Malesia, extending to Australia (Queensland) and Fiji.

Anatomy

Anatomy:

Taxonomy

Many genera are here included in Selliguea which have persistently been treated as separate. None of these correspond to any of the natural groups that can be distinguished within Selliguea.

Crypsinus, circumscribed by simple fronds, small, separate sori in a single row and indistinct main veins, contains a number of species that obviously are reduced forms of species of other genera.

Selliguea is recognised by the large, usually confluent sori in one row between the veins. Its core species is S. feei, and it would have to include all species obviously re-lated to S. feei, several of which are often classified as Crypsinus, Grammatopteridium or Oleandropsis.

Crypsinopsis, with sori in two rows between the adjacent veins, contains in this circumscription the species related to Selliguea enervis. However, small, reduced species would have to be included in Crypsinus, and in many cases their affinity to S. enervis is doubtful.

Phymatopteris is usually interpreted to include all species with pinnate fronds, as well as the simple-fronded species which are obviously related. Some of these, including its type species, C. pyrolifolius, have been included in Crypsinus. On the other hand, within the apparently natural group of pinnate species there is a considerably variability. There are much more differences between Selliguea (Phymatopteris) taeniata and S. (P.) albidosquamata than between the genera Crypsinus and Crypsinopsis; and S. (P.) triloba is in many ways more similar to S. feei (e.g., in the scales of the rhizome and the texture and anatomy of the sterile lamina) than to S. taeniata.

Pycnoloma and Grammatopteridium include the ‘drymoglossoid’ representatives of this group of ferns. Christensen (1929) already noted that Pycnoloma probably is an heterogeneous assemblage derived from several origins in either Crypsinus or Phymatopsis (Phymatopteris). All species included in Pycnoloma are small and reduced, and have no characters clearly indicating their affinity. Grammatopteridium differs from Pycnoloma in larger fronds and more complex venation (Christensen l.c.), and clearly is a dimorphic modification of a Selliguea. Christensen’s inclusion of S. brooksii under S. (Grammatopteridium) costulata demonstrates that it is hardly possible to distinguish clearly between the drymoglossoid derivatives of S. feei and those of other species of Selliguea.

Holcosorus includes all forms with narrow, gramineous fronds. Apart from Selliguea (H.) setacea and S. (H.) bisulcata, this includes forms which can be assigned to several other species of Selliguea.

There are several possibly natural groups that can be recognised in Selliguea, but also a large number of species of uncertain affinity. Selliguea feei is the central species in a relatively clear-cut group comprising S. albicaula, S. archboldii, S. bellisquamata, S. costulata, S. cretifera, S. dekockii, S. elmeri, S. feei, S. ferrea, S. lauterbachii, S. plantaginea; and S. tafana (see the notes under 17. S. feei and 32. S. plantaginea). Their main characteristics are the relatively thick coenosori, the presence of distinct hypodermises below the upper epidermis, and sometimes also the lower epidermis, the long-creeping rhizome with a thick sclerified sheath around the vascular bundles.

Selliguea enervis is, likewise, a central species in a group comprising also S. gracillipes, S. hellwigii, S. pampolycarpa, S. stenosquamis and S. subsparsa. These are characterised mainly by smallish, round sori in two rows between the veins, a more shortly creeping rhizome without sclerification around the vascular bundles. Whether S. triquetra also belongs in this group is uncertain, as it shares some characters with the group of S. feei.

Selliguea heterocarpa and S. lateritia form a distinct group, to which probably S. craspedosora and possibly S. setacea also belong, with sunken coenosori as the main distinguishing character.

Selliguea soridens and S. stenophylla form the only group that also appears to be distinct in spore morphology: in contrast to most other species, their spores have a strongly sculptured surface without globular appendages. Otherwise, this group is recognisable by the deeply sunken, round sori in a single row near the margin.

The pinnate-pinnatifid species, with the exception of S. albidosquamata and S. tri-loba, form a natural group characterised by the single sori in each main areole. To this group also belong S. pyrolifolia and S. whitfordii. Most of the species of Selliguea from Continental Asia also belong to this group (Phymatopteris of most authors), as well as S. simplicissima, from Queensland. Selliguea albidosquamata is too aberrant to include it in this group, sharing several characters with the equally isolated S. platyphylla. Selliguea triloba shares a number of characters with S. feei and S. heterocarpa, which makes its position in any of the groups aberrant.

Affinities of Selliguea are with the drynarioid ferns on the one hand, with Polypodium (not in Malesia) on the other. With the drynarioid ferns Selliguea shares the peculiar thick lamina texture of many species (with corresponding similarities in lamina anatomy, such as the presence of a distinct hypodermis below the upper surface), the non-clathrate scales, and a number of correspondences in spore-wall sculpture. There are no specific characters that distinguish Selliguea from a putative common ancestor with the drynarioid ferns, and it therefore cannot be excluded that this genus is unnatural. Smaller genera in this alliance are Arthromeris, Paraselliguea, and possibly Polypodiopteris.

Citation

Copel., Gen. Fil. 1947: 208
Copel., Fern Fl. Philipp. 1960: 500
Ching - in Sunyatsenia. 1940: 261
H. Itô - in J. Jap. Bot. 1935: 98
Ching - in Acta Phytotax. Sin. 1964: 181
Copel., Fern Fl. Philipp. 1960: 507
Ching - in Sunyatsenia. 1940: 265
Ching - in Sunyatsenia. 1940: 260
Ching - in Acta Phytotax. Sin. 1964: 181
Ching - in Sunyatsenia. 1940: 261
Hennipman et al. - in Kramer & Green, Fam. & Genera Vasc. Pl. 1990: 214
Copel., Gen. Fil. 1947: 208
C. Chr. - in Dansk Bot. Ark. 1929: pl. 8, f. 7; pl. 11, f. 1
Holttum - in Revis. Fl. Malaya. 1954: 156
Copel., Gen. Fil. 1947: 205
J. Sm., Hist. Fil. 1875: 101
C. Presl, Epim. Bot. 1851: 145
Copel., Gen. Fil. 1947: 208
Copel., Gen. Fil. 1947: 207
Copel., Gen. Fil. 1947: 209
Blume, Enum. Pl. Javae. 1828: Addenda et emendanda
Holttum - in Revis. Fl. Malaya. 1954: f. 96-103