Question

The largest living tree on earth is
A. Eucalyptus regnans
B. The giant oak
C. Sequoia gigantea
D. Juniperus

Answer 1

Hint: Swamp gums are the largest trees. These are inhabitants of Tasmania and Victoria, Australia. They prefer low temperature and their species consist of medium-sized to very tall forest trees.

Complete answer: Eucalyptus regnans is an evergreen plant having fast growth. Eucalyptus regnans is found to be the tallest of all other eucalyptus species. The species prefer growing in cold, hilly areas with over 1,000 millimetres rainfall per year. The plant has a straight, smooth, grey trunk but crumbling or less fibrous barks are present at the base which extends to around 5-20 m (16-66 ft). Typically the trunk gets to a diameter of 2.5 m (8 ft 2 in). The regrowth of young plants is accompanied with leaves that are egg-shaped and glossy green. These leaves are held horizontally and they measure 55-120 mm (2.2-4.7 in) in length and 22–50 mm (0.87-1.97 in) in width. Leaves are attached to plant stems with the help of petiole. On the other hand, adult leaves are held in an alternate manner along stems. Leaves are sickle-shaped or lance-shaped. Both sides appear glossy green. Their length is 90-230 mm (3.5-9.1 in) and width is 15-50 mm (0.59-1.97 in). These are found tapering towards a reddish petiole which is 8-25 mm (0.31-0.98 in) in length. Numerous irregularly-shaped, circular or tiny oil glands are found to be present on both upper and lower surfaces of the leaves which gives leaves a dotted appearance. Midvein gives rise to the secondary veins. However, there is very sparse tertiary venation.
Eucalyptus regnans is the largest tree which grows to a height of 230–374 feet. Sequoia gigantea has an average height of 164–279 feet; Giant oak height ranges in between 60 and 100 feet whereas Junipers range in size between 66 to 131 feet.
Hence, the correct answer is option “A” . The largest living tree on earth is Eucalyptus regnans.

Note:
Eucalyptus regnans is a plant species with broad-leaves. These are trees growing throughout the year. They normally grow to a height of 230–374 ft without forming lignotuber.