Confusion surrounding the coastal Habenaria, Bonatea and Liparis IDs: separating them by leaf structure

@tonyrebelo @milewski @markheystek @justinponder2505 @ren_hoekstra @malthinus @jeremygilmore @seroff55 @erickmunro @christiaan_viljoen @dhoare @sedgesrock

Author's note:
I have not written a scientific article before- this is my first attempt, so please bear with me and any mistakes I might have made. If you have any helpful comments or constructive criticism please send me a message on inat or mail me at ludwigxem@gmail.com .

I saw the need for an article addressing the considerable confusion surrounding Habenaria, Liparis and Bonatea IDs on inat- see https://www.inaturalist.org/observations/105954597 , https://www.inaturalist.org/observations/76911000 and https://www.inaturalist.org/observations/68596478 . This article aims to address that need.

I will be focusing on 3 species- Liparis remota, Bonatea speciosa and Habenaria arenaria. Other species in these genera that might/also occur here are Habenaria laevigata, Habenaria falcicornis, Habenaria lithophila and Liparis capensis- based on records from The Cape Orchids (Liltved & Johnson 2012). They also list a few other Habenarias that I think are too unlikely to occur here so have not included them.
Liparis capensis is excluded because of its limited range in our area- see https://www.inaturalist.org/observations?place_id=126458&subview=map&taxon_id=589246 - and also because I have no personal experience with this species. I lack notes, photos, fieldwork etc.
Habenaria laevigata has been recorded from Ruitersbos, north of Mossel Bay- not coastal
H.lithophila occurs along the mountains, not the coast.
H. falcicornis was reported from Keurboomstrand (Forest Hall, J. Vlok) and might well be worth searching for, but I lack the necessary photos and fieldwork on this species.

I will start by selecting my "type" observations- observations that, beyond doubt, are identified correctly.
Liparis remota:
https://www.inaturalist.org/observations/105900057
https://www.inaturalist.org/observations/77615173
https://www.inaturalist.org/observations/69093840
Habenaria arenaria:
https://www.inaturalist.org/observations/102165332
https://www.inaturalist.org/observations/77233833
https://www.inaturalist.org/observations/40175587
Bonatea speciosa:
https://www.inaturalist.org/observations/105953127
https://www.inaturalist.org/observations/105953111
https://www.inaturalist.org/observations/102870148
https://www.inaturalist.org/observations/100070252

Flowering time is also important:
B. speciosa flowers from June to December, in the Garden Route mostly from September to November
H. arenaria flowers from (Mar) April to July (Sep)
L. remota flowers from November to March, but in our area mostly January and Febraury

When flowering the species can easily be told apart. Unfortunately the young Bonateas most frequently confused with Habenaria have not yet reached flowering age. I was helped enormously by a recent visit to Nature's Valley, where I found all three species growing side by side in coastal forest on leaf litter and sand. Here are the main differences:

Liparis remota:
Prominent grooves/stripes running the length of the leaf.
Lack of spots on the leaf.
Most plants have two leaves, rarely three.
The leaves are normally parallel to the ground, at some height off above it. The leaves are almost never pressed close to the ground.
The tip is also, in most cases, reflexed/recurved underneath the leaf, presenting a blunt apex.
This is the smallest orchid of the three in this article, although confusion might arise with a smaller Habenaria vs a large Liparis.
Underside of leaf is a light green.

Habenaria arenaria:
Single groove/stripe running up the center of the leaf.
Approximately 60-75% of most large Habenaria populations in our area is composed of plants with white spots/ speckles on the leaves. The remaining minority has plain green leaves. This creates much confusion with the other two, especially in the coastal habitat where all grow together.
Plants normally have one, often two and rarely three leaves.
The leaf tips in a two leaved plant normally point in opposite directions.
The leaves tend to be either flattened to the ground or raised to an angle of about 30 degrees. Exceptions occur in low light conditions, where the leaves reach higher to about 40 degrees.
The leaf apex is mostly sharp and pointed.
This is the 2nd largest of the three orchids, especially when flowering.
Underside of leaf pale whitish- green to white.

Bonatea speciosa:
In young plants a single groove runs the length of the leaf, from base to apex.
At the base of a stem there is almost always ( I have never found it missing) a black sheath encasing the area below the leaves. A very reliable method of identification.
In most plants except the very young there are more than 2 leaves. Also, these leaves radiate outwards in all directions and the plant is normally at some height off the ground.
The leaves of B. speciosa are almost never pressed flat against the ground. Even in young plants the leaves are raised, the tip being higher off the ground than the base.
The leaf is rounded in older plants and even in younger plants the tip is not sharp.
This is the largest of the three species, reaching roughly 50cm in height when fully grown.
Underside of leaf whitish.

Key:

  • 1. Black "sheath" around basal portion of stem....... B. speciosa
    -Sheath absent....... 2

  • 2. Leaf with single vein running down the center....... H. arenaria
    -Multiple veins present....... L. remota

Hopefully this article will help clear up some of the confusion regarding these species on iNat. Identifying orchids from leaves only is difficult at the best of times- example https://www.inaturalist.org/observations/90529635 ( I thought it was S. coriifolium due to the raised leaves but a visit to the site when the plants were in flower showed otherwise).
If anyone needs help identifying orchids please feel free to tag me. I have enjoyed compiling this article and hopefully you've enjoyed reading it ;)

Publicado el febrero 14, 2022 01:26 TARDE por ludwig_muller ludwig_muller

Comentarios

Hi Ludwig, Many thanks for this helpful contribution. I look forward to your next Post, with regards from Antoni.

Publicado por milewski hace más de 2 años

Thanks for your reply! I am looking forward to writing my next article- hopefully dealing with the confusion surrounding Crassula expansa and one of its forms which may deserve specific status. See https://www.inaturalist.org/observations/105713801

Publicado por ludwig_muller hace más de 2 años
Publicado por tonyrebelo hace más de 2 años

Agregar un comentario

Acceder o Crear una cuenta para agregar comentarios.