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''Lepuropetalon'' is a genus of flowering plants in the family Celastraceae as that family was defined by the Angiosperm Phylogeny Group in 2009.〔Angiosperm Phylogeny Group. 2009. "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". ''Botanical Journal of the Linnean Society'' 161(2):105-121. .〕 Before the publication of the APG III system in 2009, ''Lepuropetalon'' had been placed with ''Parnassia'' in the family Parnassiaceae,〔Mark P. Simmons. 2004. "Parnassiaceae" In: Klaus Kubitzki. ''The Families and Genera of Vascular Plants'' volume VI. Springer-Verlag. Berlin,Heidelberg: Germany.〕 now usually treated as a segregate of Celastraceae. ''Lepuropetalon'' has only one species, ''Lepuropetalon spathulatum''.〔Stephen A. Spongberg. 1972. "Lepuropetalon" pages 458-461 In: "The Genera of Saxifragaceae in the Southeastern United States". ''Journal of the Arnold Arboretum'' 53(4):409-498.〕 It is a winter annual that is most abundant in eastern Texas and western Louisiana. From there, it occurs sporadically southward into Mexico, and eastward thru the Atlantic and Gulf coastal plain, and rarely in the Piedmont Plateau, to North Carolina.〔Daniel B. Ward and Angus K. Gholson. 1987. "The Hidden Abundance of ''Lepuropetalon spathulatum'' (Saxifragaceae) and Its First Reported Occurrence in Florida". ''Castanea'' 52(1):59-67.〕 It has a disjunct distribution. In addition to the area mentioned above, it is also found in Uruguay and central Chile. It is one of the smallest of terrestrial flowering plants〔George M. Diggs Jr., Barney L. Lipscomb, and Roger J. O'Kennon. 1999. ''Illustrated Flora of North Central Texas'' page 988. Botanical Research Institute of Texas and Austin College.〕 and some consider it to be the smallest.〔David R. Morgan and Douglas E. Soltis. 1993. "Phylogenetic relationships among members of Saxifragaceae sensu lato based on rbcL sequence data". ''Annals of the Missouri Botanical Garden'' 80(3):652.〕 Due its small size, petiteplant has been used as a common name. Because it is so easily overlooked, it is probably much more abundant than records indicate.〔 It is found in moist areas, usually in soils that are sandy or derived from granite. It is common along the edges of soil-filled depressions on top of rocks.〔 It is often seen in cemeteries and clearings for power lines. Because it is common in habitats that are maintained by humans, but not intensively cultivated, it is probably more abundant now than it was naturally.〔Alan S. Weakley. "Parnassiaceae" In: ''Flora of the Carolinas, Virginia, and Georgia'' (title varying with update). pages 492 and 493. (see External links below).〕 In the United States and Mexico, the seeds germinate in January. It has been suggested that this is a response to increasing day length, but no experiments have confirmed it.〔 Flowering is in March and early April. Seed maturity follows quickly. Few plants survive beyond the end of April.〔 == Description == ''Lepuropetalon spathulatum'' is a diminutive winter annual. In favorable conditions, it forms a hemispherical tuft, up to 2 cm tall and wide, rarely larger.〔 It often consists of no more than a single flower above a few tiny leaves, the whole plant being less than 5 mm high and 5mm across.〔 The stems, leaves, and flowers are conspicuously dotted with epidermal sacs of tannin that tend to be arranged in lines. These are golden-brown〔 or slightly reddish in color.〔 The stems are rather thick and slightly angled. The leaves are alternate or subopposite in arrangement, sessile, long, and wide at the end like a spoon or spatula. The flowers are solitary on the ends of stems, immediately above the leaves, and usually face upward. They are large compared to the rest of the plant, 2 to 3mm in diameter with male and female parts both present and functional.〔 The calyx consists of five broad, often unequal sepals that are joined in the lower part to form a floral cup that encloses the lower half of the ovary and is thickened along its fissures to form five ribs. The sepals persist beyond the maturity of the fruit. The petals are scale-like, white and barely visible, on the rim of the floral cup between the sepals, or sometimes absent. They die but remain, along with the sepals. The five stamens are short and opposite the sepals. Initially, they are turned inward and dump their pollen on the ovary. Eventually, they are bent outward by the expansion of the ovary.〔 The anthers are yellow, erect, and subglobular. The five staminodes are opposite the petals and dilated at the ends. The gynoecium is unilocular and composed of three fused carpels. The ovules are numerous and attached near the margins of the carpels. The three stigmas are separate or initially joined at the base, but soon separating with growth of the ovary. The stigmas are commissural, meaning that the area that is receptive to pollen extends downward along the fissures where the carpels are joined. The fruit is a capsule. The seeds are numerous and cylindrical, .15 to .2mm long, reddish when immature, and nearly black when ripe.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lepuropetalon」の詳細全文を読む スポンサード リンク
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