Tafsir of Ar-Rahman 55:11

In them are fruits—this is a new proposition intended to confirm what the previous sentence indicated regarding the earth being established for the benefit of mankind. It has also been said that it is a hal (state) intended for the future, derived from the earth or its pronoun. In that case, it is better for the prepositional phrase to be the hal itself, and "fruits" (fākihatun) to be in the nominative case as the subject (of an implied verb). The nunation (tanwin), with the help of the context, serves to indicate multiplicity; that is, in them are many varieties of things with which one finds pleasure.

And the date palms with sheaths (al-akmām): These are the containers for dates—meaning the spathe—according to what has been narrated from Ibn Abbas. It is the plural of kimm, with a kasrah on the kaf (though it may also be dammah). This applies to the kimm of fruit. As for the kumm of a garment, it is only with a dammah. Alternatively, it refers to everything that covers and encloses, such as the fiber, the palm fronds, and the spathe, for these are things from which benefit is derived, as are the covered fruits and the palm hearts, for example. Al-Mukhtār preferred the latter interpretation, and from what has been mentioned, the benefit of the description is known.