No plant species are currently documented as strictly endemic to Uzbekistan alone.
Define “endemic” as found only in one place. Using a country boundary as the test removes many candidates. Many Central Asian plants occur across Uzbekistan and neighboring countries. Modern checklists and global databases therefore do not list any species as exclusive to Uzbekistan.
Expect technical and historical causes. Political borders are recent and do not match plant ranges. Taxonomy changes move names and ranges, and many species first described from Uzbekistan are later found in adjacent Kazakhstan, Turkmenistan, Tajikistan, or Kyrgyzstan. Major sources (Kew POWO, GBIF, IUCN, Flora of Central Asia, and Uzbek checklists) treat most taxa as regional endemics rather than country-only endemics.
Look instead at close alternatives that do exist. Species restricted to the Nuratau Mountains, the Gissar–Zarafshan ranges, or the Kyzylkum Desert are real and important. Many plants are endemic to Central Asia as a whole, or they appear as endemic subspecies and local varieties recorded in national checklists. Explore regional endemics, mountain- and desert-restricted species, and authoritative databases (Kew POWO, GBIF, IUCN, Flora of Central Asia) for the best near-match lists.

