Here's another view of the same thing:

it looks like a leaf that got stuck in the sheath as it was coming out, so it got bent down and it could not unroll in time.
on the first pic i see the tip still stuck in the sheath.
it happens sometimes. not sure why. you can try to help it a bit - but it's very easy to break off the leaf altogether.
at least it DID come out. it grows quite slowly - so it should open up in a a few days.

Petrushka,
I seem to remember a recent thread where self-header type philos were doing the same thing. In your opinion,would an increase in humidity help remedy this? I know it wouldn't hurt a philo(and anthuriums for that matter)to be encapsulated for a while anyway,..but I wonder if dry household air isn't what's causing this phenomenon.

What do you think?

i have asked about this problem before.
my caladiums indoors sometimes do it. i've got a new anthurium that was doing it on a few leaves and now i have i calla lily doing it on some leaves only.
the obvious answer that comes to my mind is that they do it if kept too dry when leaves are emerging.
but mine are all on self-watering wicks - so they are never too dry. and they still do it, but only occasionally.
then i thought may be it's some nutrients lacking? so a gave them an extra ironite feed. i am feeding anthuriums/calla with bloom fert that is smth like 15-30-..smth . caladiums are on even 15-15-15 usually.
and i have good humidity: never lower then 60-65% and it's been 70-75% for the past 4 weeks. so it can't be the humidity, at least not in my case. and some leaves are still doing it. may be warmTH? temps? anthuriums love to be above 75F. and mine ARE on heat pads - they are blooming and we still have cold nites here - temps by the windows drop to 65F - so i am keeping them warm.
so in short (after a lengthy ramble..) - i still do not have the answer and nobody ever provided one either.
what's your temps and humidity and soil moisture levels?

Temps around 70 - 80F,humidity likely bad low(I'm using a portable space heater to warm my room),moisture has been on the dry side as I'm scared of overdoing it with the watering(winter and all). My indoor conditions are NOT good for a comparison at all.

However...

Have you ever had it happen in a terrarium? I know humidity would/could be really high in one,so if you've had it happen at 100% then humidity really CAN'T be the issue. I've never seen it happen in one of my terraria,but that doesn't really mean anything...unless it does.

What if 65% isn't enough?

Sorry if I seem to have a one track mind,it's just that I don't know that we can rule it out yet.

Many thanks for the feedback. I was beginning to think I had an ET in my flowerpot! Humidity might well be the answer -- I'm in an apt. in NYC that often gets too hot & dry -- I can work on that. Thanks again!

yes, i agree for anthuriums 65% humidity is like the min, 85% would be MUCH better, and even 95% at that! after yesterday downpour here my humidity indoors shot up to 80%!
i've never had a real terrarium, but i do start my dormant african masks in shoe boxes with water in the bottom 1/2" AND on heat mat to get roots to 85-90f? AND bagged. i get condensation too - so that's my only 100% pseudo-terrarium. and my afro's don't ever kink :).
but on the really huge mature ones not bagged the leaves sometimes get stuck when unrolling sideways, since they are very crinkled. but later on in the season leaves are nice and flat. only the very 1st ones get in trouble. which is usually when temps are lower - only to 70-72F day and 68F at night. may be that's too low?
i remember that philo thread - they kept saying that they will 'grow out of it'.
i have a new syngonium cutting, just potted up a month ago - it's pushed out 2 new leaves, both had the same trouble as OP - stuck at the tip. i had to push them out and they are not perfect any more :(.
may be it's nutes? iron? it seems to be happening on most of my aroids at some time or other. except 'xanadu'.
but that one has even more problems...
asleep, if yours temps are in 70-80F range all your aroids should be growing and taking more water, unless you have 65F nites. it has to be closer to 68F.

The heater is blowing away nonstop. Temps prolly stay around the same 24-7.

At the risk of digressing,..what's wrong with your xanadu?

then it's def not winter anymore :), you can water them, or they'll dry up too much! i never allow my aroids to even get semi-dry. well, only if they are bagged and its' 65F and i am away.
xanadu... i posted, but nobody had much to say..
i have some kind of leaf-spotting since i bought it last july. best i found nursery beds in fl are infected and certain kind of fungicide will kill it off. what i had full-spectrum did not work, i'll need to go get smth new soon.
oh, i bare-rooted and changed all soil too.
i sprayed and soaked, endlessly. it's better, but not by much.
currently i am doing neem spray/root soak twice a week - already for 4 weeks at least. still just a bit better.
pic on left (was away, no treatment-very bad), on right - now, a little better.
i also been cutting off as many worst infected leaves as i dared.
i think i need to get captan or some others ( i have a list, waiting for spring re-stock ;)).

Here is a link that might be useful: orig xanadu post

i know it's off-topic(not about the tip problem), but may be it'll help smbody, when they see 'chicken poxed' plants like my poor xanadu.
i figured it out finally what pest was eating my xanadu: it's greenhouse thrips! i actually saw them crawling on the underside of leaves. they also spread onto 2 of my amaryllises.
so i applied indoor systemic that i use for african violets: it should work.

This post was edited by petrushka on Mon, Jun 23, 14 at 22:37

Off topic or not,I linked this thread from back at the HP forum,because the thread resurfaced where that info was relevant...Cindy posted about it back in january.

Here is a link that might be useful: Leaves Won't Open on Philodendron Moonlight