Hoover’s Cryptantha was an annual, 5 to 20 cm tall plantlet with simple or branched stems and linear leaves that inhabited grassland communities on sandy soil.
Hoover’s Cryptantha was last recorded in 1939 and may be extinct, however, the species is said to be hard to identify, so there’s some hope that it may still exist but may just have been overlooked so far.
Greyish Forget-me-not (Myosotis traversii var. cinerascens)
The Greyish Forget-me-not, a subspecies of Traver’s Forget-me-not (Myosotis traversii Hook. f.), was restricted to exposed limestone cliff faces in the semi-alpine Castle Hill Basin in Canterbury, South Island, New Zealand.
The plant is known only from a handful of specimens collected in the 18th and 19th century, it was not found since and is thought to be possiblky extinct.
The Grand Junction Cat’s-Eye was found only twice in 1892, both times somewhere around the city of Great Junction in Mesa County, Colorado, USA.
The original type locality is not really known, however, all presumed localities are more or less completely destroyed due to agricultural and urban development, the species was never found again and is considered most likely extinct.