From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Tamarisk ( ’çshel ). This name occurs in RV [Note: Revised Version.] (only) three times;   Genesis 21:33 AV [Note: Authorized Version.] ‘ grove ,’ mg. ‘tree’;   1 Samuel 22:6 AV [Note: Authorized Version.] ‘tree,’ mg. ‘grove’;   1 Samuel 31:13 AV [Note: Authorized Version.] ‘tree.’ The RV [Note: Revised Version.] rendering is based upon an identification of the Heb. ’çshel with the Arab. [Note: Arabic.] ’âthl . RVm [Note: Revised Version margin.] gives ‘tamarisk’ for heath of EV [Note: English Version.] in   Jeremiah 17:6 (cf.   Jeremiah 48:6 ), but probably a species of juniper is intended here. There are some eight species of tamarisks in Palestine; they are most common in the Maritime Plain and the Jordan Valley. Though mostly but shrubs, some species attain to the size of large trees. They are characterized by their brittle feathery branches and minute scale-like leaves.

E. W. G. Masterman.

Webster's Dictionary [2]

(n.) Any shrub or tree of the genus Tamarix, the species of which are European and Asiatic. They have minute scalelike leaves, and small flowers in spikes. An Arabian species (T. mannifera) is the source of one kind of manna.

Holman Bible Dictionary [3]

Tamarix syriaca  Genesis 21:33 1 Samuel 31:13 1 Samuel 22:6

Easton's Bible Dictionary [4]

 Genesis 21:33 1 Samuel 22:6 31:13

Kitto's Popular Cyclopedia of Biblial Literature [5]

International Standard Bible Encyclopedia [6]

tam´a - risk  : (1) אשׁל , 'ēshel (  Genesis 21:33 , the King James Version "grove," margin "tree";  1 Samuel 22:6 , the King James Version "tree," margin "grove";  1 Samuel 31:13 , the King James Version "tree"). The Revised Version (British and American) translation is due to the similarity of 'ēshel to the Arabic 'athl, "the tamarisk." (2) ערער , ‛ar‛ār ( Jeremiah 17:6 margin (compare   Jeremiah 48:6 ), English Versions of the Bible "heath" (which see)). The tamarisk ( Tamarix , with various species in Palestine, chiefly T. Syriaca ) is a very characteristic tree of Palestine, especially in the Maritime Plain, near the sea itself, and in the Jordan Valley. Eight species are described. They are characterized by their brittle, feathery branches and by their tiny scale-like leaves. Some varieties flourish not infrequently in salty soil unsuited to any ordinary vegetation.