font settings and languages

Font Size: Large | Normal | Small
Font Face: Verdana | Geneva | Georgia
Languages:

Guilleminea densa aggregata

Interesting Facts

[ Back to top ]
 

Description

[ Back to top ]

Family Amaranthaceae

Herbs, clambering subshrubs , shrubs , or lianas. Leaves alternate or opposite, entire, exstipulate . Flowers small, bisexual or unisexual , or sterile and reduced, subtended by 1 membranous bract and 2 bracteoles, solitary or aggregated in cymes. Inflorescences elongated or condensed spikes (heads ), racemes , or thyrsoid structures of varying complexity. Bracteoles membranous or scarious . Tepals 3-5, membranous, scarious or subleathery, 1-, 3-, 5-, or 7(-23) -veined. Stamens as many as tepals and opposite these, rarely fewer than tepals; filaments free , united into a cup at base or ± entirely into a tube , filament lobes present or absent, pseudostaminodes present or absent; anthers (1- or) 2-loculed, dorsifixed , introrsely dehiscent . Ovary superior, 1-loculed; ovules 1 to many; style persistent , short and indistinct or long and slender; stigma capitate, penicillate , 2-lobed or forming 2 filiform branches. Fruit a dry utricle or a fleshy capsule, indehiscent, irregularly bursting, or circumscissile. Seeds lenticular , reniform , subglobose, or shortly cylindric , smooth or verruculose .

About 70 genera and 900 species: worldwide; 15 genera (one introduced ) and 44 species (three endemic, 14 introduced) in China.

Morphology of the androecium, perianth (tepals), and the inflorescence has traditionally been used to circumscribe genera and tribes . Pseudostaminodia are interstaminal appendages with variously shaped apices. Filament appendages are the lateral appendages of filaments (one on each side) . The basic structure of the inflorescence is the cyme (branchlets arising from the bracteole axils, the bracteoles serving as bracts for upper flowers), which can be reduced to one flower with two bracteoles and a bract. Units of dispersal vary considerably (capsules opening with lower part persistent, flower and bracteoles falling together, or cymose partial inflorescences breaking off above bract) and can be characteristic for genera. Several genera possess long trichomes serving dispersal at the base of the tepals.[1]

Genus Guilleminea

Herbs, perennial . Stems prostrate [or ascending ], much-branched, indumentum of simple hairs . Leaves opposite, petiolate ; blade linear to lanceolate, spatulate , or ovate , margins entire; basal leaves withering. Inflorescences axillary , sessile, few-flowered glomerules ; bracts and bracteoles membranous. Flowers bisexual ; tepals 5, connate proximally ± 1/2 its length , 1-veined; stamens 5; filaments connate basally into tube , tube adnate to calyx distally; anthers 2-locular; pseudostaminodes absent; ovule 1; style 1, ca. 0.2 mm; stigmas 2-lobed, capitate. Utricles broadly ovoid , membranous, indehiscent. Seeds 1, red-brown, lenticular-orbicular.

Species 5: North America, Mexico, West Indies.[2]

Taxonomy

[ Back to top ]

Similar Species

[ Back to top ]

Members of the genus Guilleminea

ZipcodeZoo has pages for 3 species, subspecies, varieties, forms, and cultivars in this genus:

G. densa (Cottonflower) · G. densa var. aggregata (Small Matweed) · G. densa var. densa (Small Matweed)

More Info

[ Back to top ]

Further Reading

[ Back to top ]

Notes

[ Back to top ]

Contributors

Identifiers

Footnotes

  1. Bojian Bao, Thomas Borsch & Steven E. Clemants "Amaranthaceae". in Flora of China Vol. 5 Page 415. Published by Science Press (Beijing) and Missouri Botanical Garden Press. Online at EFloras.org. [back]
  2. Steven E. Clemants "Guilleminea". in Flora of North America Vol. 4 Page 406, 437. Oxford University Press. Online at EFloras.org. [back]
Last Revised: 2012-07-28