I would like to offer another interesting perspective on the sensation of heat in one particular group.
A search for IRRITABILITY in the Monocots gives the following result ... remedies from the Araceae family.
* Neurosis, Irritable from tobacco, calad, [+8 Others]
* Mind; Irritable, cross: arum-t, [+30 Others].
* Mind; morose, sulky, cross, fretful, ill-humor, peevish; eating, after:, arum-m, calad [+12 Others]
Irritation and Burning sensations are found in many rubrics throughout the Araceae family (Arum-t, Arum-m, Calad, Dracon, Ictodes). Irritation and burning are particularly found in the mucous membranes and in the skin.
When I checked I found that this is due to needle-like calcium oxalate crystals which can pierce these membranes. Chewing the leaves of these plants causes irritation, swelling, breathing difficulties and convulsions.