| 词条 | Opuntia fragilis |
| 释义 |
|image = Opuntia_fragilis_1.jpg |genus = Opuntia |species = fragilis |authority = (Nutt.) Haw. |synonyms = Cactus fragilis Opuntia brachyarthra }}Opuntia fragilis, known by the common names brittle pricklypear and little prickly pear, is a prickly pear cactus native to much of western North America as well as some eastern states such as Illinois, Iowa, Wisconsin and Michigan. It occurs in several Canadian provinces. It is known from farther north than any other cactus,[1] occurring at as far as 56°N latitude in British Columbia.[2] There is an isolated and possibly genetically unique population in Eastern Ontario known as the "Kaladar population".[3] DescriptionBrittle pricklypear is a small decumbent cactus that grows to a maximum height of {{convert|10|cm|in|abbr=on}}.[4] Both the common and scientific names refer to the easily detached stem segments. This is known to be a means of plant dispersal.[4] Opuntia fragilis is a small, prostrate plant, rarely more than {{convert|4|in|cm|abbr=on|order=flip}} high: joints tumid, fragile, easily detached, oval, elliptical, or subglobose, {{convert|1|-|2|in|cm|0|abbr=on|order=flip}} long and nearly as thick as broad, bright green: areoles {{convert|1/4|-|1/2|in|cm|1|abbr=on|order=flip}} apart, with whitish wool and a few white to yellow bristles, which are much longer and more abundant on older joints; spines 1–4, occasionally a few small additional ones, weak, dark brown, the upper one usually longer and stronger than the others, rarely {{convert|1|in|cm|abbr=on|order=flip}} in length: flowers greenish yellow, {{convert|1|-|1+1/4|in|cm|1|abbr=on|order=flip}} wide: fruit ovate to subglobose. with few spines or bristles, mostly sterile, {{convert|1|in|cm|abbr=on|order=flip}} or less long; seeds few and large. Rocky Mountain region from Canada to New Mexico.[5]Subspecies and varieties
References1. ^C.Michael Hogan. 2011. Cactus. Topic ed. Arthur Dawson. Ed.-in-chief Cutler J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC 2. ^Gorelick, R. 2015. Northern range limit of Opuntia fragilis and the Cactaceae is 56°N, not 58°N. Madroño 62(2):115-123. 3. ^Mottiar, Y., P.D.J. Chafe and Eric Ribbens. 2015. Imperfect flowers of Opuntia fragilis in Kaladar, Ontario. Haseltonia 20:22-25. 4. ^1 32. Opuntia fragilis (Nuttall) Haworth, Flora of North America 5. ^Haw. External links{{Commons category}}{{Wikispecies}}
19 : Opuntia|Cacti of Canada|Cacti of the United States|Flora of Western Canada|Flora of the Northwestern United States|Flora of the North-Central United States|Flora of the Southwestern United States|Flora of the Great Lakes region (North America)|Flora of the Great Plains (North America)|Flora of California|Flora of the Cascade Range|Flora of Michigan|Flora of New Mexico|Flora of Ontario|Flora of the Rocky Mountains|Flora of Texas|Plants described in 1819|Taxa named by Thomas Nuttall|Garden plants of North America |
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