Dendrosenecio keniensis

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Dendrosenecio keniensis
Dendrosenecio keniensis mtkenya 09.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Genus: Dendrosenecio
Species:
D. keniensis
Binomial name
Dendrosenecio keniensis
(Baker f.) Mabb.
Range of Senecio keniensis.svg
Range of S. keniensis in Afrotropic
Synonyms

Dendrosenecio brassicaB. Nord.
Senecio brassicaR.E.Fr. & T.C.E.Fr.
Senecio keniensisBaker f.
Lobelia gregorianaBaker f.
Sources: [2] [3]

Contents

Dendrosenecio keniensis (syn. Senecio keniensis and S. brassica) is one of the giant groundsels endemic the higher altitudes of Mount Kenya. It is in the family Asteraceae and the genus Dendrosenecio (previously a Senecio ). Dendrosenecio keniodendron occurs the upper alpine zone of Mount Kenya and D. keniensis in the wetter areas of the lower alpine or the moorlands. [4] [5]

Description

Leaves and stems
Prostrate (even subterranean) trunks of soft brittle wood, [6] with trunk to 5 centimetres (2.0 in) in diameter; [7] which branch repeatedly at or below ground level, forming a large prostrate clone. [4] The branches each support a great cabbage-like, [6] densely packed leaf-rosettes of 30–40 leaves; each branch cloaked with older, dead foliage. Branches produced near ground-level are capable of rooting that supports a "creeping" horizontal growth-form. [7] The leaves are oblong and narrow slightly where they attach to the rosette; they can be up to 56 centimetres (22 in) long and 18 centimetres (7.1 in) wide. The leaves are capable of secreting limited quantities of a mucilaginous fluid containing polysaccharides. The upper leaf surface has a hair cushion which is also often coated with dried mucilage. The lower surface is covered densely with a thick, white felty covering of lantate[ check spelling ] hairs. [7] Growth rates are very slow. [4]
S. keniensis is frost resistant to −10  °C (14  °F ) [8] This ability to withstand the colder temperatures that occur in the upper altitudes of Mount Kenya is in part due (at least in Lobelias) to the large amounts of mucilage which are contained by the rosettes of leaves which that might assist in preventing the leaf bud from freezing and the reservoir of fluid from evaporating. [9] As well as the nyctinastic behavior of the leaf rosettes which open during the day and close tightly around the leaf bud and meristem when it becomes cold at night; [4] the outer leaves bend inwards and form around the central leaf bud. [10]
Flowers
Tall terminal spikes of groundsel flowers arise from each of the great cabbage-like rosette of leaves, [6] each spike or inflorescence narrowly conical up to 110 centimetres (43 in) tall and 20 centimetres (7.9 in) in diameter. The flower heads are upright (as opposed to pendulous in D. keniodenron) [4] each consisting of 12 to 16 bright yellow ray florets up to 25 millimetres (0.98 in) long and 60-80 disc florets. [7] Each leaf rosette dies after flowering, but the plant lives on because its highly branched growth form consists of multiple rosettes. [4]

Distribution

Senecio keniensis makes its home mostly in the lower alpine or moorland zone located at altitudes of 2,900 metres (9,500 ft) to 3,800 metres (12,500 ft) [4] [5] that can be characterized by high soil moisture, a thick humus layer, similar terrain, and not a lot of different species present. The upper alpine zone, 3,800 metres (12,500 ft) to 4,500 metres (14,800 ft), is more topographically diverse, and contains a more varied flora, including the giant rosette plants Lobelia telekii and L. keniensis , Senecio keniodendron and Carduus spp.. S. keniensis can be found in both the lower and upper alpine zone, [11] although it is less common above 4,000 metres (13,000 ft) where it can regularly hybridise with S. keniodendron . [4] [12]

Name confusion

S. keniensis has a history which includes some confusion between it and other species from other genus which belongs to a different family. There was a mix-up in some of the materials that were collected that united the leaf of Lobelia gregoriana with the inflorescence of S. keniensis.

At that time, Senecio keniensis was rejected as a confused name "nomen confusum" based on the muddled samples from which made it impossible to select a single specimen, [13] but that practice is no longer permitted and the replacement name S. brassica is superfluous and other names that were based on this basionym are similarly illogical and incorrectly deduced. Examples: Fries and Fries (1922) cited the confused material for S. brassica; Hedberg (1957) selected a single specimen from among the syntypes that associated S. brassica with Fries & Fries. [7]

Hybrid

Related Research Articles

<span class="mw-page-title-main">Mount Kenya</span> Highest mountain in Kenya

Mount Kenya is an extinct volcano in Kenya and the second-highest peak in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian, Nelion and Point Lenana. Mount Kenya is located in the former Eastern and Central provinces of Kenya; its peak is now the intersection of Meru, Embu, Kirinyaga, Nyeri and Tharaka Nithi counties, about 16.5 kilometres south of the equator, around 150 km (90 mi) north-northeast of the capital Nairobi. Mount Kenya is the source of the name of the Republic of Kenya.

<i>Dendrosenecio keniodendron</i> Species of flowering plant

Dendrosenecio keniodendron or giant groundsel is a species of the genus Dendrosenecio of the large family Asteraceae and is one of the several species of giant groundsels endemic to the high altitudes of the Afrotropics, including Dendrosenecio johnstonii (Senecio battiscombei) occurring on Mount Kilimanjaro, Mount Kenya, and the Aberdare Mountains, Dendrosenecio keniensis occurring the lower alpine zone of Mount Kenya and D. keniodendron occurring in higher and drier sites on Mount Kenya. The giant rosette plants, sometimes 6 metres (20 ft) tall, often grow in even-sized stands, with different understory communities under different-aged stands.

<i>Senecio keniophytum</i> Species of flowering plant

Atop of Mount Kenya Senecio keniophytum is one of the endemic groundsel (Senecio) found at high altitudes in Kenya, such as the Afro-alpine zone of Mount Kenya, but not one of the giant Dendrosenecio that also live there.

<i>Dendrosenecio battiscombei</i> Species of flowering plant

Dendrosenecio battiscombei is one of the giant groundsels that lives on the slopes of Mount Kenya and the Aberdare Range. Like Dendrosenecio adnivalis on the Ruwenzori Mountains and the Virunga Mountains, Dendrosenecio battiscombei grows in the lower wetter areas of the Afro-Alpine zone.

<i>Lobelia deckenii</i> Species of plant in the family Campanulaceae

Lobelia deckenii is a species of flowering plant in the family Campanulaceae. It is a giant lobelia endemic to the mountains of Tanzania. It is listed as a threatened plant of the forests of Cherangani hills, Kenya. 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.

<i>Lobelia telekii</i> Species of flowering plant

Lobelia telekii is a species of flowering plant in the family Campanulaceae, that is found only in the alpine zones of Mount Kenya, Mount Elgon, and the Aberdare Mountains of East Africa. It occurs at higher altitudes on well-drained sloped hillsides. It is a semelparous species, putting all its reproductive effort into producing single large inflorescence up to 3 metres (10 ft) tall, and then dying. Inflorescences of L. telekii also possesses a large pith-volume for internal water storage and marcescent foliage which could provide insulation. It secretes a polysaccharide into this reservoir, which may be useful for its survival in the cold climate. The plant is named after the Austro-Hungarian explorer, Count Sámuel Teleki.

<i>Dendrosenecio</i> Genus of flowering plants

Dendrosenecio is a genus of flowering plants in the sunflower family. It is a segregate of Senecio, in which it formed the subgenus Dendrosenecio. Its members, the giant groundsels, are native to the higher altitude zones of ten mountain groups in equatorial East Africa, where they form a conspicuous element of the flora.

<i>Senecio tamoides</i> Species of vine

Senecio tamoides, also known as Canary creeper, is a climbing member of the genus Senecio of the family Asteraceae that is native to Southern Africa. It is used as an ornamental plant for its showy yellow, daisy-like flowers in late autumn through to winter. Other names for the plant include golden shower vine, false grapevine, and parlor ivy.

Dendrosenecio meruensis is one of the East African giant groundsel, this one is endemic to the slopes of Mount Meru. Once they were considered to be of the genus Senecio but since then have been reclassified into their own genus Dendrosenecio.

Dendrosenecio cheranganiensis is one of the East African giant groundsel, this one endemic to the Cherangani Hills. Once it was a genus of Senecio but has recently been reclassified as a Dendrosenecio.

<i>Dendrosenecio elgonensis</i> Species of flowering plant

Dendrosenecio elgonensis is one of the giant groundsel of East Africa; this one is endemic to Mount Elgon. They used to be considered part of the genus Senecio but recently have been reclassified to their own genus, Dendrosenecio.

<i>Dendrosenecio erici-rosenii</i> Species of plant

Dendrosenecio erici-rosenii one of the East African giant groundsel and this one can be found on the Rwenzori Mountains, Virunga Mountains and the Mitumba Mountains. It is a species of the genus Dendrosenecio and is also a collection of reclassified Senecio species.

<i>Dendrosenecio kilimanjari</i> Species of flowering plant

Dendrosenecio kilimanjari is a giant groundsel found on Mount Kilimanjaro in Africa, below 4,000 metres (13,000 ft).

Dendrosenecio johnstonii, formerly Senecio johnstonii, is a species of giant groundsel found in the middle altitudes of Mount Kilimanjaro in Africa. A recent botanical reclassification split off some species formerly in Senecio, putting the giant groundsels in the new genus Dendrosenecio. It also redefined the former species Senecio cottonii, as a subspecies of Dendrosenecio johnstonii. Both genera are in the family Asteraceae. The giant grounsels of the genus Dendrosenecio evolved, about a million years ago, from a Senecio that established itself on Mount Kilimanjaro, with those that survived adapting into Dendrosenecio kilimanjari. As it moved down the mountain, the adaptations necessary for the new environment created the new species, Dendrosenecio johnstonii. Various subspecies are found on other mountains.

<i>Dendrosenecio adnivalis</i> Species of flowering plant

Dendrosenecio adnivalis is one of the giant groundsels of the mountains of Eastern Africa. D. adnivalis grows on the Rwenzori Mountains and on the Virunga Mountains in Uganda and the Democratic Republic of Congo.

Dendrosenecio brassiciformis is a species of East African giant groundsel. It is endemic to the slopes of Aberdare Range and bearing fruit but once, and dying after. Once considered to be of the genus Senecio but since have been reclassified into their own genus Dendrosenecio.

<span class="mw-page-title-main">Natural history of Mount Kenya</span>

The flora and fauna of Mount Kenya are diverse, due to the variation in altitude, rainfall, aspect and temperature. The mountain slopes can be divided into vegetation zones, with each zone having different dominant plant species. Although many plants on Mount Kenya have local names, here they are reported only with their English and scientific names.

<i>Haplosciadium</i> Genus of flowering plants

Haplosciadium is a monotypic genus of flowering plants in the family Apiaceae (Umbelliferae). Its only species is Haplosciadium abyssinicum. It is a flat rosette plant endemic to the Afro-alpine zones on East African mountains, occurring on moist valley bottoms above 3,500 metres (11,500 ft). It engages in geocarpy as an adaptation to living on frost-heaved soils.

<span class="mw-page-title-main">Rwenzori–Virunga montane moorlands</span> Montane ecoregion in central Africa

The Ruwenzori-Virunga montane moorlands is a montane grasslands and shrublands ecoregion of the Rwenzori Mountains and Virunga Mountains in central Africa.

<i>Carex monostachya</i> Species of sedge

Carex monostachya is a species of sedge native to the mountains of East Africa.

References

Sketch by John Walter Gregory of giant groundsel (Senecio keniodendron) from The Great Rift Valley Gregory003.jpg
Sketch by John Walter Gregory of giant groundsel (Senecio keniodendron) from The Great Rift Valley
  1. ↑ Williams, E.; Crook, V. (2016). "Dendrosenecio keniensis". IUCN Red List of Threatened Species . 2016: e.T63923702A63934910. doi: 10.2305/IUCN.UK.2016-3.RLTS.T63923702A63934910.en . Retrieved 20 November 2021.
  2. ↑ "Dendrosenecio keniensis (Baker f.) Mabb. record n° 105268". African Flowering Plant Database. 1986. Archived from the original on 2013-01-15. Retrieved 2008-03-27.
  3. ↑ "Senecio keniensis Baker". Nomenclatural Data Base. Missouri Botanical Garden. 1894. Retrieved 2008-03-27.
  4. 1 2 3 4 5 6 7 8 Alan P. Smith; Truman P. Young (1994). "Population biology of Senecio keniodendron". In Philip W. Rundel; Alan P. Smith; F.C. Meinzer (eds.). Tropical Alpine Environments: Plant Form and Function. Cambridge University Press. ISBN   0-521-42089-X.
  5. 1 2 Mizuno, Kazuharu. "Vegetation Succession in Relation to Glacial Fluctuation in the High Mountains of Africa" (PDF). African Study Monographs (Suppl.30): 195–212. Retrieved 2008-03-28.
  6. 1 2 3 4 Gregory, John Walter (1896). "The Flora of British East Africa". The Great Rift Valley: Being the Narrative of a Journey to Mount Kenya and Lake Baringo with Some Account of the Geology, Natural History, Anthropology and Future Prospect of British East Africa. Routledge. ISBN   0-7146-1812-8.
  7. 1 2 3 4 5 "Entry for Dendrosenecio keniensis (Baker f.) Mabb". African Plants. Ithaka Harbors. Archived from the original on 2013-08-01. Retrieved 2008-03-28.
  8. ↑ Bannister, Peter (2007). "A touch of frost? Cold hardiness of plants in the Southern Hemisphere" (PDF). New Zealand Journal of Botany. 45 (1). The Royal Society of New Zealand: 1–33. doi: 10.1080/00288250709509700 . S2CID   85259353. 0028825X/07/45010001. Retrieved 2008-03-28.[ dead link ]
  9. ↑ Young, Truman P.; Van Orden Robe, Susan (September 1986). "Microenvironmental Role of a Secreted Aqueous Solution in the Afro-Alpine Plant Lobelia keniensis". Biotropica. 18 (3). The Association for Tropical Biology and Conservation: 267–269. Bibcode:1986Biotr..18..267Y. doi:10.2307/2388496. JSTOR   2388496.
  10. ↑ Beck, Erwin; Senser, Margot; Scheibe, Renate; Steiger, Hans-Martin; Pongratz, Paul (June 1982). "Frost avoidance and freezing tolerance in Afroalpine 'giant rosette' plants". Plant, Cell & Environment. 5 (3). Blackwell Publishing: 215–222. doi:10.1111/j.1365-3040.1982.tb00913.x (inactive 2024-09-28).{{cite journal}}: CS1 maint: DOI inactive as of September 2024 (link)[ dead link ]
  11. ↑ World Conservation Monitoring Centre (April 1997). "UNEP-WCMC Protected Areas Programme -- Mount Kenya". United Nations Environment Programme. Archived from the original on 2008-05-10. Retrieved 2008-03-27.
  12. ↑ Young, Truman P.; Peacock, Mary M. (March 1992). "Giant senecios and alpine vegetation of Mount Kenya". Journal of Ecology. 80 (1). JSTOR: 141–148. Bibcode:1992JEcol..80..141Y. doi:10.2307/2261071. JSTOR   2261071.
  13. ↑ Natural Resources Conservation Service. "Frequently Asked Questions -- definition for nomen confusum". The PLANTS Database. United States Department of Agriculture . Retrieved 2008-03-28. nomen confusum (Latin): confused name. Based on heterogenous elements from which it is impossible to select a lectotype.
  14. ↑ "Senecio keniensis Baker subsp. keniensis x S. keniodendron R.E.Fr. & T.C.E.Fr. ex Hell. record n° 98700". African Flowering Plant Database. Retrieved 2008-03-27.[ permanent dead link ]

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