Distribution

State & island distribution

Based on normal state and island boundaries. Using state distribution is reasonably reliable. Tasmania is excluded as there are no Mistletoes in Tasmania

Biogeographic Districts (IBRA7)

This is the Interim Biogeographic Regionalisation for Australia, Version 7, produced in 2012. Distribution data for each taxa were sourced from the Atlas of Living Australia. While useful, should not be used as a reliable identification tool.

Habit

Aerial stem parasite

A typical mistletoe clump growing from the branch of a host tree or shrub with “roots” growing into the branch.

Erect to spreading

The plant is growing up from the haustoria or tending to sprawl sideways. Leaves and branches more horizontal and upright than obviously dropping downward.

Pendulous

The leaves and branches are dropping downwards rather than spreading sideways.

Plant characters

Epicortical runners

These are root-like structures that grow like a vine along the outside of the host branch, attaching themselves at regular intervals to the branch.

Stem internodes.

Cross section

The section of stem between the leaf nodes. Can be terete (cylindrical), angular or flattened.

Flattened internodes may be flattened in the same plane between nodes or alternate the plane of flattening at the nodes.

Terete: (cylindrical)

Rounded internodes can be smoothly rounded or rough, with small nodules and rough patches.

Angular

Angular internodes can be square in cross section or with the sides concave producing a more extreme angular form.

Flattened alternately

The nodes are obviously flattened and the direction (plane) of flattening changes are each node. Each flattened internode is at right angles to the previous.

Flattened in one plane

All the internodes are flattened in the same direction.

Hairs

A hand lens is needed to determine whether hairs are present or not. There are many different types of hair and their location on the plant is diagnostic. They can be powerful in separating some species, but some hairs are not obvious, especially those at the base of the flower ie on the ovary.

Located on leaves

Either one or both sides of the leaf has hairs, usually the lower one. Hairs can sometimes disappear from one side with age. Other parts of the plant may or may not have hairs, but the whole plant is not covered in hairs.

Located on young shoots

Hairs are located all over the young shoots. Other parts of the plant may or may not have hairs, but the whole plant is not covered in hairs.

Located on whole plant

The hairs are located on all parts of the plant, with the exception of the older stems. The hairs often give the plant a grey colouration.

Located on flowers

Hairs are located on the flowers. This may be just a small ring or patch at the base of the flowers, on the ovary or calyx.

Other parts of the plant may or may not have hairs, but the whole plant is not covered in hairs.

Located on whole of inflorescence

Hairs are located all over the inflorescence, including the corolla, peduncle, pedicels and bracts. Other parts of the plant may or may not have hairs, but the whole plant is not covered in hairs.

Located on fruit

Hairs are located on the fruit. Other parts of the plant may or may not have hairs, but the whole plant is not covered in hairs.

Inflorescence characters

Inflorescence position

The point on the stem where the inflorescence originates, either axillary or terminal. It is not always obvious that the inflorescence is axillary or terminal.

Axillary

The inflorescence originates from the axil of the leaf, between the petiole and the stem.

All Amyema sp have axillary inflorescences.

Terminal

The inflorescence originates at the end of the stem, usually between two leaves or two shoots. In mistletoes, Muellerina sp., Notothixos sp. and one Korthalsella have terminal inflorescences.

Inflorescence type.

The branching pattern of the main inflorescence axis. Ignore secondary and tertiary branching when selecting this character.

See glossary for definition of terms.

Umbel

Amyema congener shows a typical mistletoe umbel. The flowers are in triads and the flower stalks (pedicels) arise from a common point.

Some of the flowers in an Amyema triad may be sessile (typically the centre ones).

Raceme

The primary axis of this Decaisnina brittenii inflorescence is a raceme, with secondary groupings of triad umbels along it.

Spike

This Korthalsella papuana spike shows an unbranched inflorescence with flowers arranged along the stalk. As in a typical spike, the flowers are sessile.

Cluster

The structure of a cluster is indeterminate and, as in this cluster of Dactylophora novae-guineae, the flowers are usually sessile.

Flower grouping and number

The number of flowers borne on the ultimate branch of the inflorescence. In the illustrated example, an Amyema, there are three flowers (a triad). In other genera they are borne singly, in pairs or fours.

Peduncle

The peduncle is the stalk of the inflorescence. Select an inflorescence with open flowers. Measure from the twig to the first branching (see image). If the peduncle is absent, enter 0 mm. You can enter a range of measurements taken from multiple inflorescences on the same plant (e.g. 6-9 mm)

Pedicellate or sessile

The pedicel is the stalk of an individual flower. If the pedicel is absent (i.e. length = 0 mm), the flower is deemed sessile. In some species the central flower of a triad is sessile and this is a useful diagnostic character.

Pedicel length -mm

The pedicel arises either directly from the stem or branching from the peduncle. Measure in millimetres from the branching point to the base of the flower.

Inflorescence bracts

The bracts at the base of the central flowers enlarge to become leaf like (foliaceous) and partly or wholly enclose the flowers. Characteristic of the genus Diplatia.

Floral characters

Number of floral parts

The floral number is the number of petals and/or sepals that form the corolla. The stamens may or may not equal this number.

Corolla in mature bud not tubular

The petals are not fused to form a tube, or the petals are very small or absent.

Corolla in mature bud tubular

The petals are fused to form a tube when in mature bud. This tube may be slightly curved, or straight.

Inflation of mature tubular bud

In a mature tubular bud the corolla tube may be wider (inflated) in the middle than at the ends.

Corolla length

The length of corolla tube and petals in a newly opened flower. All flowers with a corolla less than 3mm are in the Santalaceae family apart from Ileostylus (found in Norfolk Island).

Petal tips

As the flowers open the petal tips split and curve away.

Recurved

The petal tips curve backwards towards the base of the corolla. The degree of recurve varies but is significantly greater than right angles to the corolla tube.

Erect

The petal tips open slightly and remain pointing upwards forming a “crown” effect.

At right angles

The tips curve back to approximately 90^o or right angles to the corolla tube.

Petal fusion

In bud, the petals are fused together to form a corolla tube. When the flower opens, the corolla splits to varying degrees, freeing the petals.

Completely free

In a fully open flower, the petals split open to the base of the flower. In some cases the split is not apparent without close observation.

United to centre or above

In a fully open flower, the petals only split to about half-way down the corolla tube or a point somewhat above. The corolla tube may be split to the base on one side only.

United up to lower 4mm

In a fully open flower, the petals split open to about 4mm above the base of the flower.

Flower gender

The sex of the flowers, determined by presence of male parts (stamens) and/or female parts (ovary, style and stigma).

Bisexual

The flowers have both male and female parts (bisexual)

Unisexual

The flowers are either male or female.

Anther connection

The anthers, pollen bearing parts, are usually borne on stalks called filaments.

Basifixed

The anthers are joined to the filaments at the base of the anther.

Dorsifixed

The anthers are joined to the filaments at the back of the anther.

Calyx, sepals, tepals

The length of the calyx, sepals or tepals is measured in mm. from the base of the calyx to the tip of the sepals/tepals.

Flower colour

If a flower has two or more colours along or within the corolla, then all the colours were recorded, but it is best to use the most obvious in the key. Some colours are a little subjective and many mistletoes have a range of flower colour. A useful characteristic but not completely reliable.

Leaf characters

Leaves: present or absent

In some of the Santalaceae, the leaves are greatly reduced or are absent. All the Loranthaceae have leaves.

If the leaves are so greatly reduced as to be not obvious, the taxa has been scored as leaves absent.

Present

All Loranthaceae have typical leaves and most of the Santalaceae have typical leaves or greatly reduced leaves (scale leaves)

Absent

In some of the Santalaceae the stems are flattened, green and perform the function of leaves. Viscum articulatum is a typical example of a mistletoe without leaves. See image.

Typical leaf features

All Loranthaceae and some Santalaceae have typical or “normal” leaves. The following describes features associated with “normal” leaves.

Arrangement

The sequence that the leaves are organised in relation to each other along the stem.

Alternate

The leaves are attached alternately on opposite sides of the stem.

In Dendropthoe sp. the leaves may be alternate or opposite to each other. D. acacioides, see image, has the most obvious alternate leaf arrangement.

Opposite

The leaves are attached in pairs opposite each other on the stem. Dendropthoe sp. tend to have a variable leaf arrangement that may be opposite or alternate.

Whorled

More than 2 leaves are attached at the same node on the stem.

Shape and section

Typical leaves are usually flat, but may be terete (cylindrical), or scale like, ie small and pressed against the stem. The leaves of all Loranthaceae are either flat or terete.

Terete (cylindrical)

Leaves of mistletoes such as Amyema cambagei are terete and mimic the leaves of its’ host, Allocasuarina sp.

Scale-like

In some Viscum and Korthalsella, the leaves are reduced to scales at the nodes and look like bracts. Viscum bancroftii has a pair of boat shaped “leaves” at the node. See image.

Flat

A typical leaf, usually flat, broad, with or without a petiole. May be thin or more succulent.

Leaf colour

The apparent colour of mature leaves when fresh. This colouration is usually due to hairs.

Green

Leaves without a dense covering of hairs are normally a shade of green.

Grey

A dense covering of whitish hairs gives the leaf a grey or bluish grey colour.

Yellowish

A dense covering of yellow hairs gives the leaves a yellowish appearance.

Leaf surfaces concolourous

The upper and lower surfaces of the leaf are the same colour. Break a leaf in half and hold side by side to compare.

Petiole presence

If the leaf stalk (petiole) is not present, the leaf is sessile.

Petiole length

The petiole is measured from the attachment point at the stem to the beginning of the leaf blade. Measure several typical leaves and enter the range of values in millimetres e.g. 5-10

Venation visibilty.

The leaf veins are either clearly visible (distinct) from upper or lower leaf surface or unable to be easily seen (obscure)

Venation type

The side veins of a leaf take different patterns that can be useful distinguishing characters.

Curvinerved

Two or more curved veins arise from the base of the leaf.

Parallel

The veins run side by side without meeting. In mistletoes usually in long linear leaves.

Penninerved

The lateral veins diverge from the midrib and are parallel to each other. Similar to the barbs of a feather

Reticulate

The veins of the leaf have a net like appearance.

Leaf size

Measure several typical leaves across the widest part for the width, and from the leaf tip to the start of the petiole for the length. Enter a range of values e.g. 10-20 for each.

Fruit Characters

Shape

This refers to the mature fruit shape, usually either globular, (spherical) or ellipsoidal (oval).

The fruit of some species can be either. Pear shaped fruit are rarer

Mature fruit colour

Ensure that the fruit is mature, (soft to the touch) to use this character as nearly all immature fruit are green and hard. The colour of the mature fruit is not known for all mistletoes.

Style persistence on fruit

The style remains attached to the ovary until the fruit is mature in some species. However, it may not be present on all fruit or been removed by damage.

Habitat

The type of vegetation community in which the mistletoe and host grow. The types are as defined by Carnaham 1977 and as used in the Australian National Botanic Garden Australian Vegetation Map. https://www.anbg.gov.au/aust-veg/veg-map.html.

Closed Forest

Area dominated by closely growing trees such that there is insufficient light for understorey to grow e.g. rainforest

Open forest

Area dominated by trees but where the canopy allows enough light through for a vigorous grassy or shrubby understory.

Scrub and Heath

Area dominated by scattered low growing shrubs. Typically the arid centre of Australia.

Shrubland

Area dominated by medium sized shrubs e.g., Acacia

Woodland

Area with scattered trees and shrubs and a herbaceous or grassy understory e.g., savanna.

Host type

Some mistletoes grow only on other mistletoes (hyperparasites). For the purposes of this key, that means only other aerial mistletoes.

Host specificity

The identity of the host can be a powerful character as some mistletoes are quite specific as to their choice of host (usually at a genus level). Others grow on a wide range of hosts.

The genera of the main hosts are listed, but it would be impossible to list all possible hosts.