''Hesperoyucca'' is a small genus of two recognized species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s closely related to, and recently split from, ''

Yucca ''Yucca'' is a genus of perennial shrubs and trees in the family Asparagaceae, subfamily Agavoideae. Its 40–50 species are notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal panicles of white or whitish flo ...

'', which is in the century plant subfamily within the asparagus family.

Description

''Hesperoyucca'' is distinct from ''Yucca'' in having loculicidally dehiscent

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

and a scape more than 2.5 cm diameter with reflexed (not erect) bracts. The stigma is capitate, whereas those of ''Yucca'' split into three reflexed lobes. The glutinous

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...

is released in a sticky mass; that of ''Yucca'' species is released as single grains.Agavaceae.com
– page includes a key to''Yucca'' and the three recognised species of ''Hesperoyucca'' ''Hesperoyucca'' is also distinct in DNA analysis. The genus is native to

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

and the southwestern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. ;SpeciesClary, Karen Husum. 2001. The genus ''Hesperoyucca'' (Agavaceae) in the western United States and Mexico: New nomenclatural combinations. Sida 19(4): 839-847.
/ref> # ''

Hesperoyucca newberryi ''Hesperoyucca newberryi'', commonly known as the Grand Canyon Quixote plant or Newberry's yucca, is a plant species endemic to Arizona. It is found only in Mohave and Coconino Counties, on the walls of canyons near the Colorado River. ''Hespe ...

'' (McKelvey) Clary (syn. ''H. whipplei'' subsp. ''newberryi'', ''Yucca newberryi'' ) - northwestern Arizona #''

Hesperoyucca peninsularis ''Hesperoyucca peninsularis'', the peninsular candle or lechuguilla, is a plant species endemic to the Baja California peninsula. It is a perennial forming a rosette. It is semelparous (flowering once then dying).Clary, Karen Husum. 2001The gen ...

'' (McKelvery) Clary (syn. ''Yucca whipplei ssp. eremica'') – peninsular candle – Baja California, Baja California Sur # '' Hesperoyucca whipplei'' (Torr.) Trel. (syn. ''Yucca whipplei'') – chaparral yucca, our Lord's candle or Spanish bayonet – southern California, Baja California

Taxonomy

The taxonomy of ''Hesperoyucca'' is complex and somewhat controversial. Originally, in 1871,

George Engelmann George Engelmann, also known as Georg Engelmann, (2 February 1809 – 4 February 1884) was a German-American botanist. He was instrumental in describing the flora of the west of North America, then very poorly known to Europeans; he was particu ...

ranked "Hespero-Yucca" as a

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sign ...

of ''Yucca'' (with only one member, ''Yucca whipplei''; all other ''Yucca'' species he placed in section Eu-Yucca, with three subgroups). In 1895 he revised his classification of ''Yucca'', to four equal groups, of which ''Hesperoyucca'' was one. In 1876,

John Gilbert Baker John Gilbert Baker (13 January 1834 – 16 August 1920) was an English botanist. His son was the botanist Edmund Gilbert Baker (1864–1949). Biography Baker was born in Guisborough in North Yorkshire, the son of John and Mary (née Gilber ...

gave it the rank of

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

; in 1892 he noted that it "had better be kept as a genus distinct from ''Yucca''" (but actually retained the name ''Y. whippleii'' ic. Some authorities accept this as having erected the genus ''Hesperoyucca'', but others credit this to

William Trelease William Trelease (February 22, 1857 – January 1, 1945) was an American botanist, entomologist, explorer, writer and educator. This botanist is denoted by the List of botanists by author abbreviation, author abbreviation Trel. when Author citati ...

, who printed a taxonomic description in 1893, formally recognising ''Hesperoyucca'' as being at the same rank as, but separate from, ''Yucca''. It has taken recent DNA analysis to confirm that they are indeed genetically distinct from ''Yucca''. The splitting of ''Hesperoyucca'' from ''Yucca'' is still not widely reflected in available literature or online (for example, the British

Royal Botanic Gardens, Kew Royal Botanic Gardens, Kew is a non-departmental public body in the United Kingdom sponsored by the Department for Environment, Food and Rural Affairs. An internationally important botanical research and education institution, it employs 1,100 ...

and the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

websites do not recognise the name as current).online Plant Finder
RHS

References

{{Taxonbar, from=Q928091 Asparagaceae genera Agavoideae Flora of North America