''Dendrosenecio keniensis'' (syn. ''Senecio keniensis'' and ''S. brassica'') is one of the giant groundsels

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

the higher altitudes of

Mount Kenya Mount Kenya ( Kikuyu: ''Kĩrĩnyaga'', Kamba, ''Ki Nyaa'') is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian (), Nelion () and Point Lenana (). Mount Kenya is loc ...

. It is in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae ...

and the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

Dendrosenecio ''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 mo ...

'' (previously a ''

Senecio ''Senecio'' is a genus of flowering plants in the daisy family (Asteraceae) that includes ragworts and groundsels. Variously circumscribed taxonomically, the genus ''Senecio'' is one of the largest genera of flowering plants. Description Morp ...

''). '' Dendrosenecio keniodendron'' occurs the upper alpine zone of Mount Kenya and ''D. keniensis'' in the wetter areas of the lower alpine or the moorlands.

Description

;Leaves and stems: Prostrate (even subterranean) trunks of soft brittle wood, with trunk to in diameter; which branch repeatedly at or below ground level, forming a large prostrate clone. The branches each support a great cabbage-like, 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. The leaves are oblong and narrow slightly where they attach to the rosette; they can be up to long and wide. The leaves are capable of secreting limited quantities of a

mucilaginous Mucilage is a thick, gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion. The direction of their movement is always opposite to that of the secretion of ...

fluid containing

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with ...

s. 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 hairs. Growth rates are very slow. :''S. keniensis'' is

frost Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above- freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a g ...

resistant to 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. As well as the

nyctinastic Nyctinasty is the circadian rhythmic nastic movement of higher plants in response to the onset of darkness, or a plant "sleeping". Nyctinastic movements are associated with diurnal light and temperature changes and controlled by the circadian clo ...

behavior of the leaf rosettes which open during the day and close tightly around the leaf bud and

meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...

when it becomes cold at night; the outer leaves bend inwards and form around the central leaf bud. ;Flowers: Tall terminal spikes of groundsel flowers arise from each of the great cabbage-like rosette of leaves, each spike or inflorescence narrowly conical up to tall and in diameter. The flower heads are upright (as opposed to pendulous in ''D. keniodenron'') each consisting of 12 to 16 bright yellow ray florets up to long and 60-80 disc florets. Each leaf rosette dies after flowering, but the plant lives on because its highly branched growth form consists of multiple rosettes.

Distribution

''Senecio keniensis'' makes its home mostly in the lower alpine or moorland zone located at altitudes of to that can be characterized by high soil moisture, a thick

humus In classical soil science, humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is a kind of soil organic matter. It is rich in nutrients and retains moisture in the soil. Humus is the Lati ...

layer, similar terrain, and not a lot of different species present. The upper alpine zone, to , is more

topographic Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary sci ...

ally diverse, and contains a more varied flora, including the giant rosette plants ''

Lobelia telekii ''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 ...

'' and '' L. keniensis'', '' Senecio keniodendron'' and ''

Carduus ''Carduus'' is a genus of flowering plants in the family Asteraceae, and the tribe Cardueae, one of two genera considered to be true thistles, the other being ''Cirsium''. Plants of the genus are known commonly as plumeless thistles.

'' spp.. ''S. keniensis'' can be found in both the lower and upper alpine zone, although it is less common above where it can regularly hybridise with '' S. keniodendron''.

Name confusion

''S. keniensis'' has a history which includes some confusion between it and other species from other

which belongs to a different

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

. There was a mix-up in some of the materials that were collected that united the leaf of ''

Lobelia gregoriana ''Lobelia'' () is a genus of flowering plants comprising 415 species, with a subcosmopolitan distribution primarily in tropical to warm temperate regions of the world, a few species extending into cooler temperate regions.Huxley, A., ed. (1992 ...

'' 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, but that practice is no longer permitted and the replacement name ''S. brassica'' is

superfluous Superfluous means unnecessary or excessive. It may also refer to: *Superfluous precision, the use of calculated measurements beyond significant figures Significant figures (also known as the significant digits, ''precision'' or ''resolution' ...

and other names that were based on this basionym are similarly illogical and incorrectly deduced. Examples:

Fries French fries (North American English), chips (British English), finger chips (Indian English), french-fried potatoes, or simply fries, are '' batonnet'' or '' allumette''-cut deep-fried potatoes of disputed origin from Belgium and France. Th ...

and

(1922) cited the confused material for ''S. brassica''; Hedberg (1957) selected a single specimen from among the

syntype In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of ...

s that associated ''S. brassica'' with Fries & Fries.

Hybrid

*''Senecio keniensis'' Baker subsp. ''keniensis x S. keniodendron'' R.E.Fr. & T.C.E.Fr. ex Hell.

References

External links

* * {{DEFAULTSORT:Dendrosenecio Keniensis keniensis Endemic flora of Kenya Mount Kenya Afromontane flora