Multi-access key to the thallose liverworts and hornworts of Victoria
Introduction
The multi-access key to the thallose liverworts and hornworts of Victoria is a key to all 88 species of thallose liverworts and hornworts that are currently known to occur in Victoria, both native and introduced. The majority of thallose liverworts and all the hornworts have pad-like photosynthetic (green) parts, rather than a stem bearing two or three ranks of leaves like the leafy liverworts (which are treated in a separate multiaccess key). Additionally, hornworts when fertile have a horn-shaped capsule, not encountered among the liverworts. Some liverwort genera (i.e. Fossombronia, Petalophyllum and Treubia) are treated here as thallose liverworts, however, the thallus becomes dissected and leaf-like, resembling the form of a leafy liverwort. Fossombronia and Petalophyllum can be distinguished from the taxa treated in the leafy liverwort multi-access key by having leaf-like segments that are irregular in shape and often dissection from one leaf-like segment to the next and highly crisped giving the overall plant the appearance of a miniature lettuce. The vegetative leaves of typical leafy liverworts are all similar in shape and have similar dissection (e.g. all unlobed or all with a similar number of lobes etc.). Treubia can be distinguished from the taxa treated in the leafy liverwort multiaccess key by having fleshy leaf-like segments that are multiple layers of cells thick throughout the leaf except the margin. This differs from typical leafy liverworts that have leaves one cell thick except sometimes at the base. All three genera when fertile can also be distinguished from typical leafy liverworts by the stems bearing sporophytes away from the apex. In typical leafy liverworts the sporophyte terminates a stem or branch.
Some terrestrial lichens (a mutualistic association between a fungus (mycobiont) and a green alga or cyanobacterium (photobiont)) could be mistaken for white, brown or black-coloured thallose liverworts (particularly of the genus Riccia when dry). These liverworts will never produce saucer (apothecia) or flask-shaped (perithecia) structures on their surfaces or embedded in their thallus, whereas in the lichens these structures are often but not always present. Liverworts that can produce similar appearing structures (gemmae cups and pseudoperianths or carpocephalum) are vivid green. Lichens in Victoria are occasionally olive-, brownish- or grey-green but are not vividly green. If in doubt, a cross-section of a lichen thallus examined under a compound microscope will reveal presence of thread-like hyphae at least in a layer (the medulla) below the photobiont cells.
This multi-access key contains 48 characters to help distinguish taxa from each other with, including habitat and several morphological features both vegetative and reproductive. It differs from other (dichotomous) keys provided in VicFlora by giving the user the flexibility to choose from one of the 46 characters provided rather than the user having to commit to investigate the particular features being questioned in the dichotomous keys. This has the benefit of:
- avoiding having to answer questions relating to a feature that may not be
present in the sample when being identified, 2. potentially being able to identify a taxon without needing to comprehend the most technical terminology and 3. allowing the rapid identification of taxa with distinct features rarely encountered among the thallose liverworts and hornworts
To use the key the user selects a feature from the features in the top left Features Available panel and clicks on the state present in their specimen to be identified. Once selected this feature and state will show as being selected in the Features Chosen panel directly below the Features Available panel. To undo a selection, click on the box next to the state chosen in the Features Chosen panel to erase the tick in the box. Once a feature state is chosen all the taxa that do not possess the chosen feature state are discarded in the bottom right Entities Discarded panel and those that do possess the chosen feature state are retained in the top right Entities Remaining panel. The user continues to choose further character states present in their specimen until identification is achieved. To restart the key when finished select the restart key icon represented by the two green arrows in the top left corner of the screen.
This key was produced by Shenali Fernando during a 2022/2023 Willis Studentship placement offered by the Royal Botanic Gardens and funded by the Cybec Foundation.
General helpful hints
For the most effective use of this key the user is encouraged to read the help guides for each character and state before submitting an answer for that character and state. Help guides and photographs can be found by clicking on the page icons beside characters and states. This help will reduce the chance of misinterpretation of the character and state. Some information and definitions required for interpreting a state may be given under character so users are encouraged to read the help guide for the characters before the states. When assessing which state a character exists or taking measurements for the taxon being identified a typical mature plant part should be used. Typical is here interpreted as a close representation of the average plant in terms of size and stature in a population and a plant part that represents the average condition for that character (e.g. average width, the most frequently observed colour, etc.). For some of the characters it is possible for some taxa to possess more than one character state for the character. In such cases either correct character state can be chosen. Furthermore, when scoring characters it is best the plant is moist, not too dry or wet, otherwise certain characters such as lustre and colour can be mistaken. Both relatively straightforward and technical characters that require more expertise and access to compound microscopes are provided. Characters are grouped together in subjects, mostly based on the plant parts that they relate to. For each plant part, characters that can be assessed without a compound microscope are provided first followed by those that require a compound microscope. These latter characters are indicated with an asterisk. The least technical of the characters that don’t require a compound microscope are provided first for each plant part. These are often able to be determined without any visual aids. Characters that don’t require a compound microscope become increasingly more technical working down to the characters requiring a compound microscope (for plant parts where characters that require a compound microscope are provided). Similarly, among the characters that require a compound microscope, those that are least technical or prone to misinterpretation are provided first and become increasingly more technical working down toward the next plant part’s set of characters. Novices in thallose liverwort and hornwort identification are advised to begin with the first characters provided for each plant part or subject first before moving into the more technically demanding characters for each plant part. To help identify the specimen to be identified as quickly as possible the best option can be used. This option highlights which characters should be used first to discard the maximum number of taxa among the remaining taxa. To use the best option select the best icon given as a blue wand at the top of the screen. For some very similar species and varieties narrowing down to a single species may not be possible using this multiaccess key alone. In such instances the user can also use the dichotomous keys, descriptions and photographs provided to help distinguish between the remaining similar species.
Thallus
A set of 24 characters that refers to the broadened photosynthetic plant body.
Width
This character refers to the distance across a segment of the thallus at its widest point when the thallus is flattened. When the thallus is highly repetitively forking, the width of the thallus should be measured at the widest point before repetitive branching occurs. It is essential the thallus is hydrated and not shrunk or rolled into itself when this character is scored. Width is divided into 6 ranges.
Hair presence
This character refers to whether hairs occur on the thallus and their length when present. Hairs can be distinguished from rhizoids by being more stiff and covering different areas of the thallus. Rhizoids, on the other hand, are only present on the underside or ventral surface of the thallus, and if a distinct midrib is present, rhizoids will only form there.
Hairs present, longer than 0.5 mm
In this state the hairs on the thallus are normally longer than 0.5mm. These hairs may occur along the margin, apex (growing point of the thallus), upper or lower surface of the thallus. This gives the thallus a distinctly hairy appearance that is easily visible. For accurate scoring of this character, the species should be scored at maturity when hairs are fully grown. This includes the species Riccia crinita.
Hairs present, shorter than 0.5 mm
In this state the hairs on the thallus are normally shorter than 0.5mm. These hairs may occur along the margin, apex (growing point of the thallus), upper or lower surface of the thallus. For accurate scoring of this character, the species should be scored at maturity when hairs are fully grown. This includes the species Riccia crozalsii and Metzgeria species.
Hairs absent
In this state there are no hairs on the thallus.
Hair location
This character refers to where the hairs can be found on the thallus.
Margins or apex
In this state the hairs are found only along the margins and apex of the thallus.
Underside
In this state the hairs are found on the underside of the thallus which faces the substrate.
Upperside
In this state the hairs are found on the upperside of the thallus, facing away from the substrate.
Dorsal colour evenness
This character refers to the evenness of the colour of the dorsal or upper thallus surface. The colour of the thallus may also change with age therefore it is important to look at plant parts that are at maturity and not aged.
Dorsal surface even throughout
In this state the dorsal, or upperside, of the thallus has an even colour throughout its entirety.
Dorsal surface uneven throughout
In this state the dorsal, or upperside, of the thallus has a distinct uneven colour throughout its entirety. This can occur in the form of the margins or the midline of the dorsal thallus showing a marked colour change from the rest of the thallus.
Underside colour
This character refers to the colour of the underside of the thallus which faces the substrate. The colour of the thallus may also change with age therefore it is important to look at plant parts that are at maturity and not aged. Sometimes the thallus underside bears different coloured scales. In such cases the colour of the thallus tissue and not the scale should be scored for this character.
Upperside colour
This character refers to the colour of the upperside of the thallus. The colour of the thallus may also change with age therefore it is important to look at plant parts that are at maturity and not aged.
Thallus margins
This character refers to the outline of the edge of the thallus.
Entire
In this state the margin is smooth, not toothed or distinctly wavy.
Toothed and not undulate
In this state the thallus margin is toothed, with little projecting points coming off the margin.
Crisped
In this state the thallus margin is crisped, where the margin is very wavy and has curled up on itself.
Primary axis orientation relative to substrate
This character refers to the orientation of the main axis of the thallus relative to the substrate and comprises two states.
Erect
In this state the main axis, which may become forked or lobed, diverges away from the substrate so that if the substrate is horizontal soil, the plant appears erect. Many species with this state have an erect unbranched section of the primary axis referred to as a stipe and a branched frond section. This give the plant the overall appearance of a small tree (dendroid habit).
Prostrate
In this state the main axis of the thallus adheres to the substrate and is more or less coplanar with it.
Thickness
This character refers to the thickness of the thallus. The thickness is measured in the middle of flattened part of the thallus, not on the thallus margin or on the midrib if present.
1 cell thick
In this state the flattened part of the thallus is 1 cell thick and creating a transparent thallus. This includes Hymenophyton flabellatum, Metzgeria species, and Pallavicinia species.
Several cells thick
In this state the flattened part of the thallus is several cells thick and is often differentiated into several separate tissue layers. This includes Astrella species, Marchantia species and Riccia species.
Branching
This character refers to the branching pattern of the segments of the thallus (thallus lobes).
Simple, bifurcate or trifurcate
In this state the branching of the thallus can be simple, bifurcate or trifurcate. A simple thallus is unbranched without any lobes. A bifurcate thallus has forked once creating two lobes and a trifurcate thallus has divided once into three lobes.
Repetitively forking
In this state the thallus repetitively forks so that each resultant lobe then forks to create new thallus lobes. This results in a thallus that can have multiple points of forking.
With branches off a main thallus not terminating in a division of many dense thin segments
In this state the thallus is pinnately divided so that it has a main axis and branches that branch off at intervals on either side. These branches do not divide into multiple dense segments but remain whole. This state includes the species Riccardia crassa.
With branches off a main thallus terminating in a division of many dense thin segments
In this state the thallus has a main stem that produces branches that each end in multiple densely arranged thin segments. This state includes the species Riccardia eriocaula and Riccardia wattsiana in Victoria.
Form
This character refers to whether the thallus is dissected into leaf-like lobes or not.
Incised into leaf-like lobes or sacs
In this state, species can resemble leafy liverworts in having lobes that appear like leaves. In Metzgeria saccata these lobes are saccate.
Not incised into leaf-like lobes or sacs
This state matches hornworts and the vast majority of thallose liverworts, in which the thallus may be divided into lobes but they are not regular and leaf-like but rather look like a fork in the thallus.
Surface Ornamentation
This character refers to the pattern or ornamentation of the thallus surface.
Finely reticulate or pitted
In this state the thallus surface shows a faint network creating a reticulate pattern, often with small shallow depressions creating little and regular pits.
Honeycombed
In this state the thallus surface shows a network of joined polygons creating a honeycombed pattern that is often visible to the naked eye. This honeycombed pattern is often an indicator of air chambers within the thallus.
Channelled
In this state the thallus surface shows one or several channels. This can appear as a depression through the centre of the thallus with the margins lifted, creating a channel as in Riccia asprella. This can also be in the form of multiple raised ridges on the thallus surface creating multiple channels as in Petalophyllum preissii.
Distinct midrib
In this state the thallus or the thallus lobes shows a line through the centre, appearing similar to a leaf midrib. The midrib should be visible to the naked eye to be scored as present. This state commonly exists alongside other thallus surface ornamentation states.
None, smooth
In this state the thallus surface is smooth and even with no pattern of ornamentation.
Air pore presence
This character refers to whether or not air pores are present in the thallus. These air pores, if present, have a function of gas exchange much like stomata. Air pores may be visible to the eye on the thallus surface as small pits or holes, or they may be inconspicuous and require a microscope to see. Often they are made conspicuous by rings of differentially coloured cells that surround them.
Air pore cavities
This character refers to air pores that enlarge to have a visible cavity.
Air pores enlarging to become cavernous
In this state the air pores enlarge and collapse downwards to become cavernous. This is visible to the naked eye and gives the thallus surface deep and wide pits and a spongy texture. This state is present in species such as Riccia crystallina, Riccia cavernosa and Riccia spongiosula in Victoria.
Air pores not enlarging to become cavernous
In this state the air pores do not enlarge and collapse downwards to become cavernous. The air pores remain either inconspicuous or as small pits on the thallus surface. This is the most common state in Victoria.
Width of dorsal costa where thallus is 1 cell thick, flattened and forking*
This character refers to how many cells wide the dorsal costa or midrib of the thallus is. This character only applies for species where the thallus is 1 cell thick everywhere apart from the midrib and is flattened and forking (Metzgeria species, Symphyogyna podophylla, Podomitrium phyllanthus, Pallavicinia species and Hymenophyton flabellatum). This character, in combination with the following ventral costa width, is essential in differentiating the species of Metzgeria.
Width of ventral costa where thallus is 1 cell thick, flattened and forking*
This character refers to how many cells wide the ventral or underside costa or midrib of the thallus is. The rhizoids may need to be removed for this character to be scored. This character only applies for species where the thallus is 1 cell thick everywhere apart from the midrib and is flattened and forking (Metzgeria species, Symphyogyna podophylla, Podomitrium phyllanthus, Pallavicinia species and Hymenophyton flabellatum). This character, in combination with the previous dorsal costa width character, is essential in differentiating the species of Metzgeria.
Ventral scale presence
This character refers to membranous flap that may be present on the ventral side or underside of the thallus. The scales, if present, cover the rhizoids and aid transport of water and nutrients along the ventral thallus. These ventral scales, if present, can differ in colour and form however they are always against the ventral thallus surface. You may need to run forceps along the ventral thallus surface to pry the scales away from the thallus to make the scales more noticeable and in order to accurately score the various ventral scale characters.
Ventral scale colour
This character refers to the colour the ventral scales can take.
Ventral scale extent
This character refers to how much of the area of the ventral thallus the ventral scales cover.
Expansive, extending beyond the margins and/or covering the entire ventral thallus
In this state the ventral scales cover a large extent of the ventral thallus often covering the entirety of the ventral thallus or even extending beyond the margins of the ventral thallus to the dorsal thallus.
Only along the midline of the ventral thallus
In this state the ventral scales do not cover the entirety of the thallus or reach the margins of the thallus. Instead, the ventral scales cover the midline of the ventral thallus only.
Only at apex and/or margins of the thallus
In this state the ventral scale extent is small and the scales are confined to at the apex or the margins of the thallus.
Ventral scale rows
This character refers to whether or not the ventral scales are arranged in rows along the underside of the thallus.
Ventral scales not in multiple distinct rows
In this character the ventral scales are not arranged in multiple distinct rows. In some species there are too few scales to produce clear rows or there may be only one row of scales along the ventral surface.
Ventral scales in two or more distinct rows
In this character the ventral scales are arranged in two or more rows. These rows appear as multiple scales lined in rows with ends aligned relative to the midrib or centre of the thallus.
Ventral scale lobe presence
This character refers to the presence or absence of accessory structures of the ventral scales. These may appear as lobes or appendages attached to the membranous flap that is the ventral scale.
Ventral scale lobes or appendages absent
In this state the ventral scales do not have lobes or appendages associated with them.
Ventral scale lobes or appendages present
In this state the ventral scales do have lobes or appendages associated with them.
Air chamber presence
This character refers to the presence or absence of air chambers in the thallus. Air chambers are the chamber for gas exchange, and may be unroofed over the top or roofed except for an air pore. Air chambers may be visible to the naked eye by creating a honeycombed pattern over the thallus surface with an air pore in the centre of each polygon (includes Marchantia species) or air chambers may only be visible using compound microscope, often only in transverse section.
Air chamber layers*
This character state refers to the form and the number of vertical layers of air chambers that are present in a thallus. This can only be seen in a transverse section using a compound microscope and a very thin section is required to correctly assess it.
Layer of broad air chambers
In this state there is one layer of broad air chambers that lie directly below the upper thallus surface.
Layer of narrow air chambers
In this state there is one layer of air chambers that are as narrow or narrower than the vertical partitions of photosynthetic cells that separate the chambers from each other. This is found in Riccia subgenus Riccia.
Several layers
In this state there is at least one layer of air chambers below the layer of air chambers directly beneath the upper surface. The tiers of air chambers may not form discrete layers.
Air chamber photosynthetic filaments*
This character refers to the presence or absence of photosynthetic filaments lining the floor of an air chamber. These photosynthetic filaments appear green due to chloroplasts and consist of strings of cells one on top of the other to produce a filament.
Rhizoids
This is a set of two characters that describe the rhizoids. Rhizoids are thread-like structures that attach the thallus to the substrate.
Rhizoid colour
This character refers to the colour of the rhizoids.
Hyaline to brown
In this state the rhizoids are hyaline (colourless) or brown.
Crimson to purple
In this state the rhizoids are crimson or purple. This is only encountered in Fossombronia in Victoria.
Rhizoid cell walls*
This character refers to the rhizoid cell wall type. Some species of thallose liverworts are dimorphic and possess both types of rhizoid cell wall (including genera Lunularia, Marchantia, Riccia, Astrella and Targionia in Victoria).
Incursions of internal cell wall resulting in peg rhizoids
In this state the internal cell wall of the rhizoid has thickenings that result in peg-like projections into the lumen of the rhizoid (internal cavity). These are also known as tuberculate rhizoids.
Straight, smooth cell walls
In this state the internal cell wall of the rhizoid does not have thickenings. The cell wall is smooth throughout, without incursions.
Cell
A set of two characters that relate to cell contents.
Chloroplast number*
This character refers to the number of chloroplasts that can be found in green photosynthetic thallus cells. The chloroplasts are organelles that will appear like spherical to elliptic green structures within the cell.
1 per cell
In this state there is one chloroplast per cell. Two genera in Victoria show this, the hornworts Anthoceros and Phaeoceros.
2 to 4 per cell
In this state there are 2–4 chloroplast per cell. One species in Victoria belongs to this state, the hornwort Megaceros gracilis
Numerous per cell
In this state there are many chloroplast per cell. This occurs in all thallose liverworts of Victoria.
Oil cell and constituent oil body presence*
This character refers to the presence or absence of cells with organelles containing oil (oil bodies). Oil bodies usually appear as brown circular or oblong structures in the cells. Oil bodies may only be visible in fresh material. If oils cells and constituent oil bodies are present they may be evenly scattered throughout the thallus, or confined to particular types of tissue such as only the dorsal or ventral epidermal cell layers or scales. Therefore, when scoring this character it is essential to take transverse section of the thallus before using a compound microscope to examine all cell layers in order to score oil cell and constituent oil body presence or absence.
Reproduction
This is a set of nine characters that refer to aspects of reproduction (sexual and asexual).
Gemmae presence
This character refers to the absence or presence of gemmae, specialised propagules that species produces to reproduce asexually. These appear as small green or yellow disc-like structures and may be contained in specialised structures called gemmae cups or without specialised structures and on the thallus surface.
Gemmae absent
In this state there are no discernible gemmae.
Gemmae present
In this state the thallus has gemmae.
Gemmae cup
This character refers to the structures where the gemmae are borne on the thallus surface.
Circular
In this state, the gemmae are borne only in a circular cup. Only one genus in Victoria shows this, Marchantia.
Crescent
In this state, the gemmae are borne only in a crescent-shaped cup. Only one species in Victoria shows this, Lunularia cruciata.
No gemmae cup
In this state, the gemmae are not borne or associated with any structure on the thallus surface.
Number of archegoniophore rays
This character refers to the number of rays, which are the finger-like projections or lobes, which are on the umbrella-like structures that bear the sporophytes (archegoniophores) in some thallose liverworts. This character refers to Marchantia, Asterella, Plagiochasma and Reboulia species.
Number of elongated pseudoperianth slits
This character refers to number of elongated pseudoperianth slits that surround the sporophyte. The pseudoperianth in this character appears as a white membranous covering of the sporophyte that hangs down from the rays (finger-like projections) of the umbrella-like archegoniophore. This pseudoperianth is conical and bulging, and has a number of wide vertical slits down its length, through which the spores emerge out of. This appears only in genus Asterella and is a diagnostic feature of the different Asterella species
No vertical slits
In this state there is no distinct conical pseudoperianth covering of the sporophyte that appears white and membranous with elongated slits, when the sporophyte is hanging down from umbrella-like archegonia rays. This state refers to species that have a sporophyte embedded inside the thallus or is emergent on the thallus without accessory structures such as a pseudoperianth or if they have a pseudoperianth that does not match the above description. This is all genera in Victoria except for Asterella.
Up to 8 vertical slits
In this state there are 8 vertical slits down the elongated conical pseudoperianth. This appears as a white and membranous sac that hands down from beneath each ray of the archegoniophore with 8 slits.
8 to 12 vertical slits
In this state there are 8 to 12 vertical slits down the elongated conical pseudoperianth. This appears as a white and membranous sac that hangs down from beneath each ray of the archegoniophore with 8 to 12 slits.
More than 12 vertical slits
In this state there are more than 12 vertical slits down the elongated conical pseudoperianth. This appears as a white and membranous sac that hangs down from beneath each ray of the archegoniophore with more than 12 slits.
Sporophyte position
This character refers to which part of the thallus the capsule is produced on and has four states.
Sporophyte completely enclosed in structures (flask-shaped), dominating the thallus surface
In this state the sporophyte is completely enclosed in a flask-shaped structure (equivalent to an involucre) or tube. The involucres tend to dominate the thallus, obscuring the thallus lobes. The involucre can range from inverted pear-shaped to bubble-shaped. This state is encountered in Monocarpos sphaerocarpus, Riella halophila, Riella spiculata, and Sphaerocarpos texanus.
Sporophyte embedded in thallus
In this state the sporophyte is not visible on the thallus surface and is instead embedded in the thallus. This may appear as dark, spherical bulges beneath the thallus surface. This includes Riccia species.
Sporophyte visible on thallus surface
In this state the sporophyte is positioned on the thallus surface but not elevated above the thallus. The sporophyte in this state are commonly associated with an accessory structure such as scales, bracts or an open-ended tubular structures that surround at least the base of the sporophyte (such as an involucre or psuedoperianth). This can be seen by the naked-eye and is the most common state in Victoria.
Sporophyte elevated on archegoniophore
In this state the sporophyte is elevated visibly above the main thallus surface on a typically umbrella-shaped erect extension of the gametophyte (archegoniophore).
Involucre form
This character refers to the form of the involucre which is a modified part of thallus tissue the surrounds or subtends the developing sporophyte and has a protective role. In some species multiple separate series of protective structures are associated with the sporophyte. In these cases the involucre will be the outer most series.
Involucre a ring of scales
In this state the involucre is comprises several scales that completely encircle the sporophyte.
Involucre a scale
In this state the involucre is a single scale position at the base to one side of the sporophyte.
Bilabiate or bivalvate
In this state there are two scale-like structures or a tubular structure clearly split into two lips.
Involucre absent or tubular
In this state the involucre is absent or the involucre is tubular and not split so is difficult to discern from other structures associated with sporophytes such as shoot calyptra that can also appear tubular.
Antheridia position
This character refers to the structures associated with the male organs (antheridia) that produce sperm and their position on the thallus.
Embedded in thallus
In this state the antheridia are embedded in the thallus.
On thallus, with scales
In this state the antheridia are on the thallus surface, but not elevated above the thallus. The antheridia are associated with scales which can vary in morphology from appearing as scale around the base on the antheridia to fully enclosing the antheridia in a tube-like involucre.
On thallus, without scales
In this state the antheridia are on the thallus surface, but not elevated above the thallus. The antheridia have no accessory structures associated with them and appear on the thallus surface naked.
Elevated on antheridiophore
In this state the antheridia are elevated visibly above the main thallus surface on a stalk that is an extension of the gametophyte (antheridiophore).
Antheridia location
This character relates to which thallus surface the antheridia or the male branches, which are produced to carry the antheridia, are found on the thallus.
Ventral thallus
In this state the antheridia or male branches are found on the ventral or underside of the thallus.
Dorsal thallus
In this state the antheridia or male branches are found on the dorsal or upperside of the thallus.
Thallus margin or apex
In this state the antheridia or male branches are found on the margins or apex of the thallus.
Plant sexuality
This character refers to whether both male organs (antheridia) that produce sperm and female organs (archegonia) that produce eggs are positioned on the same or different plants (gametophytes). To assess this character the archegonia and antheridia will need to be located. Antheridia are spherical or elliptic in shape and contain biflagellate sperm. Archegonia are differentiated from antheridia by their long neck protruding from the oval egg-containing section.
Antheridia and archegonia on different plants
In this state both male organs (antheridia) that produce sperm and female organs (archegonia) that produce eggs are positioned on different plants (dioicous). In liverworts that produce archegoniophores and sometimes also antheridiophores this is easily assessed because only some plants will produce the easily visible archegoniophore (umbrella-like) while on other plants no archegoniophores will be produced, sometimes instead producing easily visible flat-topped antheridiophores.
Antheridia and archegonia on same plant
In this state both male organs (antheridia) that produce sperm and female organs (archegonia) that produce eggs are positioned on the same plant (monoicous). This can be on different branches or (autoicous) or on the same branch but in different clusters (paroicous).
Seta
A single character about the stalk that the capsule is attached to.
Seta length
This character refers to the length of the stalk that leads from the foot (base of the seta that anchors the seta to the gametophyte) to the capsule, the seta. The seta tends to elongate over time therefore it is essential this character be scored at maturity. In some liverworts the capsules are borne on the underside of a conspicuous erect extension of the gametophyte (gamete producing part of the plant) called an archegoniophore, which resembles an umbrella. This is not the seta.
Longer than capsule length
In this state the seta is longer than the capsule length.
Shorter than capsule length
In this state the seta is shorter than the capsule length. The capsule can still be emergent on the thallus, but not elevated above it.
Capsule
A set of two characters that refer to the structure that contains the spores.
Capsule shape
This character refers to the shape of the capsule and is used to differentiate between hornworts and thallose liverworts.
Needle-shaped and appearing like a horn
In this state the capsule is needle-shaped, appearing in one single solid column that tapers towards the end. The overall form appears like a horn. This is the distinctive feature of hornworts, i.e. the genera Anthoceros, Phaeoceros and Megaceros.
Not needle-shaped
In this state the capsule is not needle-shaped, as described as above, but is instead globose, ellipsoid or pear-shaped. This is a feature of thallose liverworts.
Capsule dehiscence
This character refers to how the capsule opens to release the spores within.
Dehisces into 2 valves
In this state the capsule opens by two slits on its sides.
Dehisces into 4 values
In this state the capsule opens by four slits on its sides.
Indehiscent
In this state there is no clear signs that the capsule opens in a regular and predictable fashion, such as by slits, to release the spores within. Instead, the capsule wall decays or breaks down irregularly.
Spore
This is a set of four characters that refer to the morphology of the spores.
Colour*
This character refers to the colour of the spore and has four states.
Number shed*
This character refers to whether spores when shed are always stuck together in groups of the same number of spores or if each spore is shed alone.
In groups
In this character state spores are shed stuck together in groups. This state is encountered in Sphaerocarpos texanus in Victoria.
Singly
In this state spores are shed not stuck to any other spores, and so are shed singly. Often immature spores are held in groups however on maturation these groups separate and spores are shed singly, therefore it is important this character be assessed at maturity. This is by far the most common state for thallose liverworts and hornworts in Victoria.
Spore surface ornamentation*
This character refers to the pattern or ornamentation that is found on the surface of the spore.
Areolate
In this state the spore surface is covered in polygonal areas demarcated by ridges or crests.
Granulate
In this state the spore surface is covered small, rounded or irregular protuberances.
Pitted
In this state the spore surface has numerous small pits like a golf ball. Sometimes these pits can coalesce to produce shallow channels.
Flat-topped, mesa-like tubercles
In this state the spore surface has several very short crests that have a roughly flat top and so resemble mesas. They are around the same height as their length.
Lamellate
In this state the spore surface is covered by narrow crests which may be parallel to each other or connected to each other but not to the extent that an unbroken network is created.
Cerebriform
In this state the spore has numerous rounded ridges giving the spore a brain-like appearance, similar to some species of hard coral such as Platygyra.
Smooth
In this state the spore surface is smooth and lacks ornamentation.
Spinose
In this state the spore surface is spiny, covered in long, sharply-pointed projections.
Lamellate projection number*
This character refers to Fossombronia spores with crests on their surface that project beyond the circular outline of the spore like spines. These lamellate projections vary in shape from narrow to wide and truncate. This character has 4 states that relate to the number of lamellate projections.
None
There are no lamellate projections on the spore surface as the ridges that create the lamellate pattern are not raised enough to create spine-like projections.
3 to 13
There are 1 to 13 lamellate projections on the spore surface.
13 to 25
There are 13 to 25 lamellate projections on the spore surface.
Greater than 26
There are greater than 26 lamellate projections on the spore surface.
Elaters
This is a set of two characters that refer to the elaters. Elaters are thread-like cells with spiral thickenings that are contained within the capsule along with spores. These have the function of propelling spores out to aid with dispersal.
Elater presence*
This character refers to the presence or absence of elaters in the capsule. The pseudoelaters of hornworts have been scored as elaters.
Elaters absent
In this state elaters are absent.
Elaters present
In this state elaters are present. The pseudoelaters of hornworts have been scored as elaters.
Elater helix number*
This character refers to the number of spiral or helical thickenings in an elater. The elaters in the capsule of a taxon may possess elaters with different numbers of helical thickenings, and in this case all seen can be scored.
Single
In this state there is a single spiral or helical thickening of the elater.
Double
In this state there are two helical thickenings of the elaters. This appears like a strand of DNA.
Triple
In this state there are three helical thickenings of the elaters.
Four or more
In this state there are four or more helical thickenings of the elaters.
Substrate
This character refers to what surface the liverwort grows on.
Freshwater mud/soil
In this state species are found on freshwater mud or damp soil throughout areas of Victoria away from the coast.
Saline to subsaline mud/soil
In this state species are found on mud or damp soil of high salinity, typical of inland salt lakes, salt pans and coastal mud flats and samphires. This state includes the species Monocarpus sphaerocarpus, and Riella haplophila.
Rocks
In this state species grow on rocks. This might be on cliff faces or rocks that are constantly wetted in streams or waterfalls.
Trees, shrubs, logs
In this state species are epiphytic growing on some part of a tree or other plant, such as the tree or tree-fern trunk, branches or leaves, and these plant parts may be standing or have fallen.
Free-floating or submerged
Species that are largely aquatic fall within this state as they float freely on the surface of the water or are submerged. Some species that might typically fall into this state may also occur beside but above the level of the water and may also satisfy one of the other states.
Habitat
This character refers to whether a liverwort occurs in ‘dry’ or ‘wet’ habitats.
Dry (grassland, mallee, heathland, salt pan or dry sclerophyll forest)
In this character the habitat of the species has periods which are completely dry with no available surface moisture and includes grasslands, mallee, heathlands, salt pans and beaches, and dry forests. During hot, dry periods species in these habitats shrink or die back and become barely discernible, but are able to rehydrate and grow during wetter periods of the year.
Wet (riparian forest, wet sclerophyll forest or rainforest)
In this character the habitat of the species has year round moisture and includes forests and sites beside streams and rivers, wet sclerophyll forests and rainforests.