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Lecanopteris an introduction & key.

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Ant-ferns, Old World.

Lecanopteris Caspar Georg Reinwardt published in Flora 8, 1825.  Type Lecanopteris carnosa (Reinw.) Carl (Karl) Ludwig von Blume published in Enumeratio Plantarum Javae 1828. Basionym Onychium carnosum (Reinw.) published in Sylloge Plantarum Novarum 2: 3. 1828 (Actually Nov. 1825.]  This genus is yet another of the very widespread and highly innovative Polypodiaceae fern family.

  Description: Lecanopteris range from having only slightly thickened rhizomes (L sinuosa) to being quite caudiciform (having very enlarged ‘stem’ bases.) and their varied types of ant-domatia are very different in structure to the tiny rotund tubers of New World ant-house ferns.  Indeed, they sometimes trend toward the complex chamber and tunnel systems we will see in Rubiaceae sub-family hydnophytinae.  Lecanopteris rhizomes spread over or completely encircle the trunks or branches of host trees and some species can attain a considerable basal mass with overall plant sizes further enhanced when frond growth is long and lush.

  Rhizome is the word usually used for fern stems and in Lecanopteris literature.  Yet rhizomes are defined as horizontally growing stems usually found underground. If separated into pieces with an attached node each has the ability to grow roots and leaves thereby creating new clones. Stolons are very similar except that they grow above ground.

  Rhizomes are of six basic forms unequally distributed between both sub-genera; all forms have hollow chambers and tunnels that provide ant-domatia except in L. mirabilis, the only species with a solid-stemmed form that merely creates arched hollows against trees in which ant colonies choose to live.  We will see an essentially similar nesting strategy beneath bark-clasping, dome shaped leaves of some ant-house Dischidia & Hoya species.  Some Lecanopteris species have complex, dimorphic (two-form) rhizomes but the most common form of domatia, found in eleven species, is a central gallery system running the length of rhizomes and extending laterally and vertically into phyllopodia.  (Gay 1990 & 1993b, Gay & Henson 1992, Gay et al. 1994.)  Phyllopodia (singular phyllopodium) are short rhizome outgrowths that each articulate with a leaf rachis in Lecanopteris. The articulation point is where abscission and loss of old leaves takes place leaving phyllopodia in place. Here is a definition; cylindrical, vertical formations on the rhizome, like a bump on a log, and functioning as a platform for each frond attachment.

  All of these rhizome bases have a thick, waxy epidermis that helps insulate inner domatia from environmental stresses, especially the daytime heat of their typically sun-exposed tropical habitats.  They also have no stomata, which helps to prevent dehydration, especially if foliage (that has stomata) has been lost during dry season droughts.  Lecanopteris ant-domatia are dark coloured inside and are dry; moisture from ant exhalations and excretions is probably absorbed through chamber walls by osmosis.

  Infauna. In a study of seven Lecanopteris species, L. sinuosa, L. lomarioides (as L. sarcopus), L. mirabilis, L. deparioides (as L. curtisii), L. pumila, L. celebica and L. darnaedii, all were regularly ant inhabited.  A total of 31 ant species were recorded visiting the plants but of these, 20 species were noted only once. The most regular ant inhabitants were Philidris cordata, Anonychomyrna murina, Crematogaster treubi, C. difformis, and Camponotus pallidas.  All five species kept larvae in domatia (82% of plants) and deposited debris within domatia but away from brood areas (90% of plants.)  A. murina did not construct carton runways but the four other major inhabitants constructed runways around 79% of Lecanopteris specimens examined (Gay & Hensen 1992 with ant taxonomy updated.)

The presence or not of ant carton will have important bearings on seedling establishment of entire myrmeco-epiphyte guilds.

  Other Infauna. Other occasional residents were Green Ants, Oecophylla species, Pheidole ants 5 species, springtails, termites 2 species, woodlice & possibly spiders. (Gay et al. 1984 & Gay 1993b.)

  Habitats:  The genus has never been found above the tree line and all species are extreme epiphytes preferring warm, sun-exposed positions on rough barked trees.  “Daytime temperatures are an equable 18- 28oC (64- 82oF.) in the habitats of all species.”  (Gay et al. 1994.)  We will see that bright to very sunny positions are a favourite choice of epiphytic ant-house taxa and their preferred ant guests.  Ranges: Lecanopteris reside almost exclusively in the Malesian Floristic Province, with Sulawesi Island, Indonesia, being their centre of distribution.  However, one particularly adaptable and widespread species L. sinuosa extends as far northeast from Sulawesi as southern lowland Taiwan in the northern hemisphere, southeast to North Queensland, Australia and down the Solomon Islands and Vanuatu archipelagos well into the southwest Pacific Ocean.  Sympatry (species occurring together) of Lecanopteris is rare, but where geographical ranges overlap, ecological isolation often occurs.  However, see L. carnosa and L. lomarioides.

  Of the 13 known species, 8 occur in Sulawesi and 6 of these are endemic (found nowhere else); however, 5 of these are known from very few collections, so they probably have very restricted distributions.

Sulawesi Island: 8. Species, L, lomarioides, & L sinuosa; the endemics are L balgooyi, L. carnosa, L. celebica, L darnaedii, L holttumii & L spinosa.

New Guinea Island: 3 species, L. deparioides, L. mirabilis & L. sinuosa.  Borneo Island: 4 species, L crustacea, L deparioides, L. pumila & L. sinuosa.

Java Island: 2 species, L deparioides & L. sinuosa.  Sumatra Island: 4 species, L crustacea, L. deparioides, L pumila, L sinuosa.

Philippine Islands: 4 species L. deparioides, L. lomarioides, L luzonensis, and L sinuosa.

Malayan Peninsula: L. crustacea, L. deparioides, L. lomarioides, L pumila (including Thailand), L sinuosa. (Gay et al. 1994.)

  Ant farming of honeydew-producing coccids (scale insects) was found to be variable with ant and plant species; Anonychomyrna murina tended them in 50% of specimens, and honeydew producing aphids and leaf-hoppers were farmed by Crematogaster treubi (39%), C. borneensis (27%) and Philidris cordata (16%)  (Gay & Hensen 1992 with ant taxonomy updated.)

  Myrmecotrophy is the feeding of ants by plants.  Lecanopteris gain nutrients and possibly moisture from decomposing ant debris that includes ant faeces and corpses, inedible parts of animal prey, and plant scraps discarded in domatia by resident ant colonies.  Nutrients containing 14-glucose, 86-rubidium and 32-phosphorus tracers injected into fern chambers but not directly into plant tissues were seen to be absorbed and distributed throughout the plants, hence nutrients are probably absorbed through the inner walls of domatia, which however, seem to have no specialised absorptive structures of the type we will see in some hydnophyta.  Dr Gay also confirmed that Lecanopteris roots penetrate into and absorb nutrients from ant-carton runways and one species (L. spinosa) is recorded sending roots into its own domatia.  Furthermore, nutrients containing the isotope 15-N. fed directly to the ants themselves soon became incorporated within Lecanopteris tissues presumably via ant faeces.  (Gay 1993A, Gay et al. 1994.)

  Within a population of Lecanopteris, or within a particular habitat, ants tend to associate with specific plant species and a single ant species will colonise most members of Lecanopteris populations throughout the life of the plants as well as a range of other species in local myrmecophyte guilds.  (Gay & Hensen 1992, Gay et al. 1994.)  Certainly, Lecanopteris are frequent components of varied epiphytic ant-house communities.  Yet the relationships between ants and Lecanopteris are believed by some to be a result of ecology not of co-evolution.  This is because when a Lecanopteris species is distributed more widely than an ant species, another ant species takes its place  However, I believe this is incorrect and that within a complex mosaic of relationships, elements of co-evolution are occurring between at least some ant species (e.g. Philidris cordata) and some of its ant-house partners including Lecanopteris.

  There is a report that ants help to disperse the spores of Lecanopteris, probably attracted by oil in sporangium cell walls. (Richards 1996.)  See also L mirabilis.

  Defence:  Crematogaster and Philidris are tiny non-stinging ants that seem to present little deterrence to eaters of arboreal ant-house plants but the question of defence requires more field studies.

  Evolutionary relationships:  Dr Gay (1993) considered the genus is probably not monophyletic.  Phylogeny in subgenus Myrmecopteris is unclear; no gradation of rhizome complexity exists.  In subgenus Lecanopteris, L. deparioides (as L. curtisii) is considered most similar to the ancestral species, giving rise to the L. pumila group, which engendered the L. darnaedii group.

Similarly (Haufler et al. 2003,) in a DNA study found that subgenus Lecanopteris appeared to be monophyletic, but subgenus Myrmecopteris was paraphyletic.  Rhizome morphology, including surface indumentum (hairs etc), branching patterns, and internal galleries, correlated with DNA-based hypotheses of evolutionary history and interspecific relationships, but aspects of leaf morphology, including blade shape and soral position, appears to be homoplastic (although they resemble one another in outward form and function they are not derived from the same source.)  Low levels of infrageneric sequence divergence between morphologically distinct species suggest a relaxation of selective pressure on morphology perhaps owing to the ant/plant associations. Narrowly distributed, derived (further evolved) species may have arisen as peripheral isolates from more geographically widespread progenitors.

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After Gay et al. 1994 with corrected taxonomy.

1a. Rhizome with a dense or scattered covering of peltate scales that hide the rhizome colour-(sub-genus Myrmecopteris) 2

1b. Rhizome macroscopically glabrous, bright green when young, blackening with age-(sub-genus Lecanopteris) 5

2a. Rhizome solid, arched and plate-like; scales thinly scattered over surface; fronds pinnatifid-  Species 1. L. mirabilis.

2b. Rhizome completely or partly hollow, not arched and plate-like; densely covered with scales; fronds pinnatifid or entire. 3

3a. Rhizome dimorphic, consisting of solid cylindrical frond-bearing main branches and hollow, ovate, frond-less side branches; peltate scales black-centred. Fronds pinnatifid- Species 2. L. lomarioides (as L. sarcopus a synonym.)

3b. Rhizome monomorphic (single form), hollow except for apical 2- 3 cm; peltate scales black or brown centered.  Fronds pinnatifid or entire. 4

4a. Peltate scales brown-centered. Fronds pinnate; rhizome much-branched- Species 3. L. crustacea.

4b. Peltate scales black-centered. Fronds entire; rhizome much or little-branched- Species 4. L. sinuosa.

5a. Rhizome with a waxy sheen, glaucous, never spiny; extra-marginal sori boat-shaped- Species 5. L. deparioides (as L. curtisii a synonym.)

5b. Rhizome green, with scattered or dense spines derived from aborted fronds or epidermal outgrowths, hollow or solid, or with coralloid excrescences derived from aborted phyllopodia, or spineless but bearing an indumentum of glandular hairs- 6

6a. Spines or excrescences derived from modified undeveloped fronds and replacing some fronds,  in two rows along the rhizome. A single gallery system within rhizome.  Phyllopodia hollow, protruding. 7

6b. Spines derived from epidermal outgrowths densely cover rhizome. Two gallery systems in  rhizome; phyllopodia solid, not protruding. 11

7a. Spines hollow. Fronds entire to pinnatifid- Species 6.  L. balgooyi.

7b. Spines solid, or replaced by coralloid excrescences. Fronds pinnatifid. 8

8a. Rhizome covered with short coralloid excrescences l-3cm long, derived from modified undeveloped fronds. Species 7. L. carnosa.

8b. Rhizome with a more or less dense covering of solid spines, no excrescences. 9.

9a. Large stout plants, rhizome diameter 2.5-3.5 cm. Fronds up to 1 m long. Spines abundant on rhizome. Species 8. L. celebica.

9b. Small to moderate sized plants; rhizome diameter 1.5-2.5 cm. Fronds not more than 45 cm long. Spines very sparse, never abundant. 10

10a. Rhizome bearing dense indumentum of branched hyaline (thin transparent) to brown glandular hairs. Luzon Island. Species 9. L. luzonensis.

10b. Rhizome apices with an indumentum of scattered brown glandular hairs and scale. West Malesia. Species 10. L. pumila.

11a. Fronds entire with sori inserted on lamina in two rows on either side of rachis- Species 11. L. spinosa.

11b. Fronds pinnatifid with sori immersed on extra-marginal lobes or sessile on lamina. 12

12a. Veins strongly sclerified, appearing black- Species 12. L. darnaedii.

12b. Veins slightly sclerified, appearing green- Species 13. L. holttumii.


The terms "coralloid excrescences derived from aborted phyllopodia" or "short coralloid excrescences l-3cm long, derived from modified undeveloped fronds" or merely "excrescences derived from modified undeveloped fronds".  Note that these 'excrescences' are derived from very different sources.

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  • 2 months later...

I have added a note to the Lecanopteris key to help clarify the possible confusion surrounding "excrescences".

Perhaps those with access to specimens and images can clarify?  It would be helpful to have illustrations detailing these excrescences.

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Haufler, Ch; Grammer, Wa; Hennipman, E; Ranker, Ta; Smith, Ar; Schneider, H., 2003

Systematics of the ant-fern genus Lecanopteris Polypodiaceae: testing phylogenetic hypotheses with DNA sequences. Systematic botany 28(2): 217- 227.

"The rhizomes of all species in the fern genus Lecanopteris Reinw. contain galleries (hollow chambers) that serve as domatia (homes) for ants. Some aspects of the biology of these species have been elucidated clearly, e.g., adaptations linked to the facultative, co-ecological association between Lecanopteris species and ants have been well established. Other aspects such as the evolutionary relationships between Lecanopteris and other genera of the Polypodiaceae as well as among the thirteen species in Lecanopteris remain widely debated. Diverse leaf and rhizome features have provided numerous autapomorphic characters for diagnosing species and describing subgenera, but there are few synapomorphies to establish reliable interspecific alliances. DNA sequences of the rbcL gene and the trnL-F non-coding region were obtained to test hypotheses of evolutionary history for Lecanopteris and related taxa. Data from each DNA region were considered separately and in combined analyses. The phylogeny obtained from parsimony and maximum likelihood analyses of separate and combined data sets were congruent, but the analyses of combined data sets contained more informative characters, more robust bootstrap support, and better Bremer ("decay") values than did analyses of the individual DNA regions. Lecanopteris was solidly supported as monophyletic, subgenus Lecanopteris appeared monophyletic, but subgenus Myrmecopteris was paraphyletic. Rhizome morphology, including surface indument, branching patterns, and internal galleries, correlated with DNA-based hypotheses of evolutionary history and interspecific relationships, but aspects of leaf morphology, including blade shape and soral position, appeared homoplastic. Low levels of infrageneric sequence divergence between morphologically distinct species suggest a relaxation of selective pressure on morphology, perhaps owing to the ant/plant association. Narrowly distributed, derived species may have arisen as peripheral isolates from more geographically widespread progenitors".

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you have not the consensus tree from this DNA analysis ?


"I am not able to access the full article, but here is the abstract."

 Very obviously no because it is not in the abstract, but perhaps others in this group have access.  It would certainly be interesting.

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  • 3 weeks later...
I cannot provide a link but if one searches for some of  its key words (see below), it is possible to locate a copy of the following article that can be read on line or be downloaded and printed, but not in PDF format, unless one is a member of Research gate.

Haufler, Ch; Grammer, Wa; Hennipman, E; Ranker, Ta; Smith, Ar; Schneider, H., 2003. 

Systematics of the ant-fern genus Lecanopteris Polypodiaceae: testing phylogenetic hypotheses with DNA sequences. Systematic botany e 28(2): 217-227.

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  • 4 months later...


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