Dendrosenecio meruensis
Encyclopedia
Dendrosenecio meruensis is one of the East Africa
n 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
.
diameter of 2 centimeters. Leaf-rosette
s of 15 to 20 leaves which are somewhat loose around the stem. Leaf bases retained for 1 to 2 meters around the stem and below the leaf-rosette.
"Repeated reproduction and branching yields a sprawling, open canopy with up to 10–30 aerial meristem
s in mature trees." Leaf surfaces are elliptical, 113 centimeters long and 34 centimeters wide, with cushions of hair cushion weakly to strongly developed on upper leaf surface. The lower leaf surface is hairless or with slight small, soft hairs sometimes cobweb-like along lower mid-vein. Inflorescence broadly flat on the top and can be up to 100 centimeters tall with diameters of 50 centimeters. The flower heads are presented horizontally. 12 to 17 yellow
ray florets that can be up to 23 millimeters long and 40 to 65 disc florets.
.
The following was presented as a first hand view of the flora on Mount Meru:
Mount Meru
(2007): From the Arusha Region
, "3400 meters, giving way to alpine Pentaschistis
tussock grassland
. In wetter areas, and on the western slopes in deep valleys, giant groundsels (Senecio meruensis) and Lobelia deckenii
occur with many other afroalpine species such as Anemone thomsonii
, Disa stairsii
, Gladiolus watsonioides and Swertia kilimandscharica. On the drier western, northern and eastern slopes Stoebe kilimandscharica (Seriphium kilimandscharicum) bushes replace erica
ceous heath, with Artemisia afra
, Anthospermum usambarense and Adenocarpus mannii. In absence of fire, both types of subalpine heaths have a gradual transition to forests around 3000 meters altitude with isolated subalpine bush patches in the openings of Hagenia abyssinica
forest at 2700-2800 meters altitude and Hagenia abyssinica
forest patches in protected valleys at 3240 meters."
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
n giant groundsel, this one is endemic to the slopes of Mount Meru
Mount Meru (Tanzania)
Mount Meru is an active stratovolcano located west of Mount Kilimanjaro in the nation of Tanzania. At a height of , it is visible from Mt Kilimanjaro on a clear day, and is the tenth highest mountain in Africa. Much of its bulk was lost about 8,000 years ago due to an eastward volcanic blast,...
. Once they were considered to be of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Senecio
Senecio
Senecio is a genus of the daisy family that includes ragworts and groundsels. The flower heads are normally rayed, completely yellow, and the heads are borne in branched clusters...
but since then have been reclassified into their own genus Dendrosenecio
Dendrosenecio
Dendrosenecio is a genus of flowering plants belonging to the family Asteraceae. It is a segregate of Senecio, in which it formed the subgenus Dendrosenecio...
.
Description
Dendrosenecio meruensis an upright plant that can grow to 7 meters tall, with trunks up to 35 centimeters in diameter and pithPith
Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots...
diameter of 2 centimeters. Leaf-rosette
Rosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
s of 15 to 20 leaves which are somewhat loose around the stem. Leaf bases retained for 1 to 2 meters around the stem and below the leaf-rosette.
"Repeated reproduction and branching yields a sprawling, open canopy with up to 10–30 aerial meristem
Meristem
A meristem is the tissue in most plants consisting of undifferentiated cells , found in zones of the plant where growth can take place....
s in mature trees." Leaf surfaces are elliptical, 113 centimeters long and 34 centimeters wide, with cushions of hair cushion weakly to strongly developed on upper leaf surface. The lower leaf surface is hairless or with slight small, soft hairs sometimes cobweb-like along lower mid-vein. Inflorescence broadly flat on the top and can be up to 100 centimeters tall with diameters of 50 centimeters. The flower heads are presented horizontally. 12 to 17 yellow
Yellow
Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...
ray florets that can be up to 23 millimeters long and 40 to 65 disc florets.
Distribution
Found between 2850–3350 meters up the slopes of Mount MeruMount Meru (Tanzania)
Mount Meru is an active stratovolcano located west of Mount Kilimanjaro in the nation of Tanzania. At a height of , it is visible from Mt Kilimanjaro on a clear day, and is the tenth highest mountain in Africa. Much of its bulk was lost about 8,000 years ago due to an eastward volcanic blast,...
.
The following was presented as a first hand view of the flora on Mount Meru:
Mount Meru
Mount Meru (Tanzania)
Mount Meru is an active stratovolcano located west of Mount Kilimanjaro in the nation of Tanzania. At a height of , it is visible from Mt Kilimanjaro on a clear day, and is the tenth highest mountain in Africa. Much of its bulk was lost about 8,000 years ago due to an eastward volcanic blast,...
(2007): From the Arusha Region
Arusha Region
Arusha is one of Tanzania's 26 administrative regions. The regional capital and largest city is Arusha. Other towns include Monduli, just west of Arusha, Longido and Loliondo to the north, Mto Wa Mbu and Karatu to the west and Usa River to the east...
, "3400 meters, giving way to alpine Pentaschistis
Pentaschistis
Pentaschistis is a genus of grass in the Poaceae family.It includes the following species:* Pentaschistic chrysurus* Pentaschistic dolichochaeta* Pentaschistis mannii* Pentaschistis pictigluma...
tussock grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
. In wetter areas, and on the western slopes in deep valleys, giant groundsels (Senecio meruensis) and Lobelia deckenii
Lobelia deckenii
Lobelia deckenii 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...
occur with many other afroalpine species such as Anemone thomsonii
Anemone thomsonii
Anemone thomsonii is a species of Anemone from East Africa....
, Disa stairsii
Disa stairsii
Disa stairsii is a species of Disa of the family Orchidaceae that can be found growing with the giant heathers on the Ruwenzori Mountains of mountains in East tropical Africa....
, Gladiolus watsonioides and Swertia kilimandscharica. On the drier western, northern and eastern slopes Stoebe kilimandscharica (Seriphium kilimandscharicum) bushes replace erica
Erica
Erica ,the heaths or heathers, is a genus of approximately 860 species of flowering plants in the family Ericaceae. The English common names "heath" and "heather" are shared by some closely related genera of similar appearance....
ceous heath, with Artemisia afra
Artemisia afra
Artemisia afra is a common species of the genus Artemisia in Africa, with a wide distribution from South Africa, to areas reaching to the North and East, as far north as Ethiopia. Artemisia afra is the only indigenous species in this genus....
, Anthospermum usambarense and Adenocarpus mannii. In absence of fire, both types of subalpine heaths have a gradual transition to forests around 3000 meters altitude with isolated subalpine bush patches in the openings of Hagenia abyssinica
Hagenia
Hagenia abyssinica is a species of flowering plant native to the high-elevation Afromontane regions of central and eastern Africa. It also has a disjunct distribution in the high mountains of East Africa from Sudan and Ethiopia in the north, through Kenya, Uganda, Rwanda, Burundi, Democratic...
forest at 2700-2800 meters altitude and Hagenia abyssinica
Hagenia
Hagenia abyssinica is a species of flowering plant native to the high-elevation Afromontane regions of central and eastern Africa. It also has a disjunct distribution in the high mountains of East Africa from Sudan and Ethiopia in the north, through Kenya, Uganda, Rwanda, Burundi, Democratic...
forest patches in protected valleys at 3240 meters."
Infraspecific name synonymy
The names for the giant groundsels have become somewhat confusing:- Dendrosenecio meruensis (Cotton & Blakelock) E.B.Knox
- Senecio johnstonii Oliv. var. meruensis (Cotton & Blakelock) C.Jeffrey
- Senecio meruensis Cotton & Blakelock