Unpollinated palm fruits may show different traits according to the concerned palm sp. So it may be useful if we could recognize them at first glance without trying first to gather fruits and extract supposed seeds, we would save thus time an futile effort. On Phoenix loureiroi I have observed that unpollinated fruits ripen at a much slower rate, are smaller and more oblong. Accordingly pollinated fruits of same sp are bigger, have an ovoid shape and the whole infructescence of pollinated fruits looks congested (because of the larger size of the fruits). Also pollinated fruits ripen at a very fast rate, about two to three months after pollination.

Below an ifructescence which bears almost all unpollinated fruits with the exception of a couple ones

and an infructescence with almost all fruits pollinated

Just checking the fruit and seed shapes and sizes with the species description lets you know instantly wether its a normal and probably viable fruit/seed or a surely infertile one. Except with certain species that develop their fruits and seeds normally regardless,in which case only cutting seeds open would let you know if they are viable or not.

What gives to my nerves are my 2 Trachycarpus fortunei which have never set any more than 10 maybe viable seeds in the 5years I have had them. Hundreds/thousands of infertile fruits on them every year....

Bump, a grand one! In the genus Phoenix frequently all three carpels of an unpollinated flower develop to a star like empty fruit that rarely, if ever, reaches maturity. When Phoenix flowers gets pollinated all three carpels are merged to one single oval shaped fruit. Whether latter is efficiently or adequately pollinated is a different story.

Konstantinos, it's normal for some fruit to fall before it ripens, but does it depend on why they are sterile?

8 minutes ago, gyuseppe said:

Konstantinos, it's normal for some fruit to fall before it ripens, but does it depend on why they are sterile?

I have a real date palm, producing and maturing real dates. A good portion of almost mature dates is aborted just before full maturity. Although those fruits are soft, they are not tasty at all and their seeds never germinate.