Daylilies have what is called "ovarian self-incompatibility" or "late-acting self-incompatibility". When a cross is incompatible they will set pods and those pods will develop for several weeks and then they are usually aborted. Most self-incompatibility systems in other species prevent the pollen from being successful and so pods are not set when flowers are self-pollinated.

Self-incompatibility systems are also in play when daylilies are cross-pollinated if the two parents just happen to carry the necessary incompatibility factors to prevent successful pollinations.

Maurice, can you point me to somewhere I can learn more about this?

All,
I am crazy, but why not pollinate our flowers even when the temp might go above 85? Unless you have some special pollen you are saving for certain pod parents, I'd say to go ahead and use a few grains on a DL that MIGHT get too hot to set a pod. I have a lot more frozen pollen than I will ever use. Buy some $1/ matchbox packs and use them to freeze your pollen for future crosses. Plus, I have leftover fresh pollen every day, even if I wasn't going to freeze the rest.
But, what do I know?
David

Lalambchop1 said:Maurice, can you point me to somewhere I can learn more about this?

The published information specifically about daylilies is meagre. There is a very small amount on daylilies in a more general paper written by Stout, "Studies of the inheritance of self and cross-incompatibility" published in the Memoirs of the Horticultural Society of New York Volume 3 pages 345-352. The Horticultural Society has scanned its publications so that article should be available on its web-site. It is not very detailed and basically what it indicates is that the incompatibility in daylilies is complex, that self-compatible plants are typically still incompatible with some other daylilies and that crosses of A x B may fail even when the cross B x A works. It does not indicate the definition of a cross that works (ie what percentage of pollinations produce mature pods, how many seeds are present, etc.) There is some other information in another Stout paper, "Pollen Tube Behavior in Hemerocallis with Special Reference to Incompatibilities" in the Bulletin of the Torrey Botanical Club 60:397-416 1933. That is possibly available through interlibrary loan.

For more general information on ovarian/late acting self-incompatibility:
Late-acting self-incompatibility in angiosperms by Steven R. Seavey , Kamaljit S. Bawa in The Botanical Review April 1986, Volume 52, Issue 2, pp 195-219
&
Ovarian and other late-acting self-incompatibility systems by Tammy L. Sage , Robert I. Bertin , Elizabeth G. Williams in Genetic control of self-incompatibility and reproductive development in flowering plants, Volume 2 of the series Advances in Cellular and Molecular Biology of Plants pp 116-140.

I have not examined and do not know of any less scientific articles that describe ovarian/late acting self-incompatibility.

If you have general questions it might be useful to start a thread with posts asking those questions and I will answer as many as I can and/or point you to specific research papers with other species that might have appropriate information.

Thank you so much! I will seek those articles out. I really appreciate your taking the time to find and post the info I asked about.

So the day and night before when a bud is closed - and as yet unopened - but the pistol protrudes, can you pollinate successfully?

Yes you can.