Lobelia deckenii

Lobelia deckenii (syn. Lobelia keniensis) is a species of giant lobelia of the mountains of East Africa. It grows in moist areas, such as valley bottoms and moorland, in contrast to Lobelia telekii which grows in a similar but drier habitat. These two species produce occasional hybrids. Lobelia deckenii plants usually produce multiple rosettes. Each rosette grows for several decades, produces a single large inflorescence and hundreds of thousands of seeds, then dies. Because individual plants have multiple rosettes, they survive to reproduce repeatedly, and plants with more rosettes flower more frequently. It is iteroparous.[2]

Lobelia deckenii
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Campanulaceae
Genus: Lobelia
Species:
L. deckenii
Binomial name
Lobelia deckenii
Hemsl., 1877 [1]

Lobelia deckenii plants usually form between one and eighteen rosettes which are connected underground. The individual rosettes grow slowly in the alpine environment,[2] and may take decades to reach reproductive size. The rosette that produces an inflorescence dies after flowering, but the remaining connected rosettes live on.[2]

Lobelia deckenii is the only alpine species of lobelia that is native to Kilimanjaro,[3] occurring between 3,800 and 4,300 m (12,500 and 14,100 ft).[4]

Lobelia deckenii ssp. keniensis is the variety of Lobelia deckenii that occurs on Mount Kenya, between 3,300 and 4,600 m (10,800 and 15,100 ft). It is eaten less by rock hyrax than Lobelia telekii, which occurs more often in hyrax habitat. The lobelia species on Mount Kenya are both pollinated by birds,[5][6] especially the scarlet-tufted sunbird and the alpine chat.[7]

This species of giant lobelia is known for the reservoirs of water held in its rosettes, which freeze at night and protect the apical meristem which is contained in a dense central leaf bud. When this reservoir is drained, the temperature of the inner meristem drops below freezing, which does not occur when the fluid is left intact.[8] The crescent-shaped ice cubes formed in these rosettes gave rise to the nickname, "gin and tonic lobelia".

  • A water-holding giant lobelia seen from above
  • A young inflorescence, its floral bracts still intact.
  • Inflorescence of the giant lobelia, its floral bracts shredded by the feet of perching bird pollinators

References
  1. International Plant Names Index
  2. Young, Truman P. (1984). "The comparative demography of semelparous Lobelia telekii and iteroparous Lobelia keniensis on Mount Kenya". Journal of Ecology. 72 (2): 637–650. doi:10.2307/2260073. JSTOR 2260073.
  3. Young, T.P. 1991. The flora, fauna, and ecology of Mount Kenya and Kilimanjaro. Pp. 37-49 In: Guide to Mount Kenya and Kilimanjaro (Iain Allan, ed.) Mountain Club of Kenya ISBN 978-9966-9856-0-6
  4. Kilimanjaro. O rei da África. Revista Planeta, dezembro de 2005.
  5. Young, Truman P. (1982). "Bird visitation, seed set, and germination rates in two species of Lobelia on Mount Kenya". Ecology. 68 (6): 1983–1986. doi:10.2307/1940139. JSTOR 1940139.
  6. Burd, Martin (1995). "Pollinator behavioural responses to reward size in Lobelia deckenii: no escape from pollen limitation of seed set". Journal of Ecology. 83 (5): 865–872. doi:10.2307/2261423. JSTOR 2261423.
  7. Smith, Alan P.; Truman P. Young (1987). "Tropical Alpine Plant Ecology". Annual Review of Ecology and Systematics. 18: 137–158. doi:10.1146/annurev.es.18.110187.001033.
  8. Young, Truman P.; Susan Van Orden Robe (1986). "Micro-environmental role of a secreted aqueous solution in afro-alpine Lobelia keniensis". Biotropica. 18 (3): 267–269. doi:10.2307/2388496. JSTOR 2388496.
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