Anthurium anatomy basics

Here I wanted to compile some information on anthurium anatomy in a fairly concise format that I hope is easy to understand.  I tried to keep to things that I thought were either sources of confusion or are just generally useful for being able to describe anthuriums precisely without getting too granular.

Some Useful Terms

First I thought it would be useful to just lay out some basic terminology.  I won’t define terms like “leaf” or “root” as I don’t think they are big sources of confusion.

Stem- This is the main structural element of the plant from which all of the others arise.  This is the “trunk” if you will.  

Petiole- This is the stalk connecting the leaf to the stem.  This is often mistakenly called a stem.

Inflorescence- We often call this the “flower” although it isn’t truly a flower.  The actual flowers are tiny and numerous and arranged along the spadix of the inflorescence which is the firm tubular structure.  The spadix is surrounded by a modified leaf called a spathe.

Peduncle- This is the stalk supporting the inflorescence.

Seedling vs Cataphyll Growth Phases

Next I just wanted to show the basic structure of a seedling vs a more mature plant which has switched to cataphyll growth as it can be disorienting when your plant suddenly starts shooting new things out in every direction.

I’ll start with a seedling.  In seedlings, the new leaves arise from the base of the previous petiole which can be seen on this young carlablackiae seedling below.  The swelling at the base of the petiole is the newest leaf and you can see the tip just peaking out of the sheath.

When a plant matures enough to begin flowering it begins producing new leaves from the center of the plant which emerge surrounded by a modified leaf called a cataphyll.  Once this transition occurs, inflorescences may now emerge from the bases of petioles in a similar location to where new leaves emerged in the seedling growth phase.  The first petiole from which an inflo could emerge would be the one prior to the first cataphyll leaf.  Below is a labeled photo of an Anthurium antolakii (previously BVEP) which has recently transitioned to cataphyll growth.  The first inflorescence has emerged and the next inflorescence is forming in the base of the next petiole:

Leaf/Vein Anatomy

This is a topic I actually was pretty lacking on knowledge and had to do some digging to get right (hopefully).  I think it’s useful to know these terms for communicating about our plants as the vein structure is an incredibly important part of what makes certain plants attractive to us. First some definitions:

Adaxial: This would be what we consider the front/top of the leaf.

Abaxial: This is the back/undersurface of the leaf.

Midrib: This is the main central vein that arises from the petiole insertion down the midline of the leaf.

Basal Veins: These are the main veins on either side which arise from the petiole insertion.  

Secondary veins: These are second order veins not arising directly from the petiole insertion.

Primary lateral veins: These are specific secondary veins which arise directly from the midrib.

Next I have made a diagram using a nice individual from my Anthurium antolakii “round” x RA1 cross which has a prominent number of basal veins and fairly subdued lateral and secondary veins.  Plants with these features often have a “spidery” appearance.

Here is an image of my Anthurium carlablackiae plant that I call “round” Carla.  I selected this to demonstrate the primary lateral and secondary veins which are more pronounced due to the contrast venation of carlablackiae.

Finally, an abaxial image of this Nov sp DF mainly to demonstrate the geniculum which is the portion of the petiole which inserts into the leaf.  “Genu” means “knee” and this portion of the petiole can bend and twist allowing the plant to change the orientation of its leaves to control light exposure.  On certain species, this area is thickened compared to the rest of the petiole making it more conspicuous, on others it is more continuous in appearance with the rest of the petiole.  DF has a nice clear geniculum which is one reason why I selected it for this diagram.  It also nicely demonstrates a “basal rib” which is basically when multiple basal veins are conjoined or fused together where they arise from the petiole insertion.

Inflorescence

I’ll keep the text here brief.  This will just be a diagram showing the major components of the inflorescence.  Pictured is a pollinated inflorescence of an Anthurium dressleri:

And that’s all I have for now.  I will likely add to this from time to time as I think of more things.  If there’s anything else you think I missed or would be useful feel free to let me know.  

Edited 12/31/23: Fixed the definitions of secondary veins and primarily lateral veins which it was pointed out to me were vague.