Identification & Diagnosis
Reading the cleft: window margin patterns and what they tell you
The cleft is the line where the two lobes meet. Its colour, depth, and pattern are some of the most reliable identification clues in the genus.
Cleft depth as a species clue
Deep clefts that nearly bisect the body are characteristic of L. divergens, L. helmutii, and L. comptonii — species where the two lobes are pulled apart and the window sits at the inside walls more than on the top.
Shallow, almost closed clefts belong to L. optica, L. herrei, and L. ruschiorum, where the top is dominated by an undivided window. Most other species sit between the two extremes.
The cleft line — colour and continuity
A continuous dark line running along the cleft margin is diagnostic for L. julii ('kissing lips'). A red flush rather than a hard line points toward L. karasmontana var. lericheana or L. lesliei var. rubrobrunnea.
An absent or pale cleft line, with the cleft itself blending into the window, is typical of L. salicola, L. terricolor, and the dwarf species in the L. comptonii alliance.
When the cleft is misleading
Pigment expression in the cleft changes with sun stress and water status. A pale-clefted plant grown under low light may darken markedly after sun acclimation; a dehydrated plant may pucker the cleft into a sharper line than it would normally show. Read the cleft with body and window pattern, not in isolation.
Frequently asked questions
- What does a black cleft mean?
- Either a strong L. julii ssp. fulleri, a sun-darkened L. lesliei, or — rarely — early necrosis. Check the rest of the body to decide.
- Why is my cleft splitting strangely?
- Usually irregular splitting from over-feeding or interrupted molt. See the splitting guide.
- Does the cleft change with age?
- Yes. Older plants often show deeper, more pronounced clefts than young ones of the same species.
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Written by the Editorial Team. Spotted an error or want to add a regional note? Send corrections or apply to contribute.