Coprosma robusta
| Coprosma robusta | |
|---|---|
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| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Asterids |
| Order: | Gentianales |
| Family: | Rubiaceae |
| Subfamily: | Rubioideae |
| Tribe: | Anthospermeae |
| Genus: | Coprosma |
| Species: | C. robusta |
| Binomial name | |
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Coprosma robusta Raoul |
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Coprosma robusta, known by the common name karamu, is a large bushy shrub that grows up to 6 meters tall. Branches are stout with no hair. Domatia (small holes on the back of the leaf at the intersection of veins) and stipules are significant characteristic features of Coprosmas Karamu stipules are black, hairless and obtuse with slightly serrated margin that are united at the base
The glossy leaves of karamu range from 5 to 12 centimeters long, with elliptic-oblong shape and acute or obtuse leaf apex and with obvious veins (Oliver, 1935). Leaves are dark green on the blade and light green on the back (New Zealand Conservation Network, 2015) are thick, and the midrib is not raised on the upper surface.
Flowers are small and white, axillary, dense, have four lobes and have a different appearance in male and females. Male flowers are dense, glomerules with a campanulate shaped corolla and have four stamens; female flowers are compound with a tubular shaped corolla. Stigmas are obvious. The best flowering period is between August and September.
Fruit are often dark orange-red to red, oblong to narrow ovate drups. The best fruting period is between April and May.
Karamu is endemic to New Zealand. However, it is gradually becoming naturalized in areas of the south-east coast of Australia such as Victoria and Tasmania (Blood, 2001) and has been rated as a weed threat there.
It is widely distributed across New Zealand in both the North and South Islands. On the Chatham Islands between Waitangi and Owenga, there is a small area where karamu has become naturalized. They can often be observed naturally in lowland forest. Judging from the distribution map on New Zealand Plant Observation, the distribution of karamu increases with the differentiation in lower altitude which means more karamu in the North Island.
In Canterbury, karamu is found on Banks Peninsula in fragments of regenerating native bush and bush remnants. Additionally it is also found in forest margins and edges of the montane and lowland forests in the southern alps at the start of the Canterbury planes. Karamu can also be found in the urban environment of many Christchurch city green spaces (e.g. park like Riccarton Bush).
Karamu can be widely found near coastal, lowland and lower montane areas. It can also grow within shrub lands and expansive areas within dense trees such as lowland forest. However, the population decreases in lowland forest such as beech and kahikatea forests. Normally karamu is a hardy plant that can adapt to infertile soils, poorly drained and exposed lands. It can also grow in a large range of altitude varying from 0–1200 meters under full sun to shady, windy and frosty circumstances.
In New Zealand the flowering season of karamu is from winter (approximately from July) to summer (ends around December). Male and female flowers are separated which is called dioecious. Seeds mature by about April and start germinating soon afterwards and doesn't leave a long lasting seed bank.
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Wikipedia