The term "merry plant" likely refers to Dracaena fragrans 'Massangeana', also known as the Corn Plant or Mass Cane. This popular houseplant is characterized by its vibrant, variegated leaves and tolerance of a wide range of indoor conditions. It is known for its ability to remove indoor pollutants and is a common sight in homes and offices. 

Here's a more detailed description: 

Appearance:

'Massangeana' features long, arching, strap-like leaves with a central yellow stripe or variegation. The overall appearance is quite striking, with a rosette of leaves atop a sturdy, cane-like stem.

Growth:

This plant can grow to several feet tall indoors, but its growth is relatively slow and manageable.

Care:

Dracaena fragrans 'Massangeana' is relatively easy to care for, thriving in bright, indirect light and tolerating low light conditions. It prefers well-draining soil and should be allowed to dry out slightly between waterings.

Benefits:

It is known for its air-purifying qualities, helping to remove formaldehyde, xylene, and toluene from indoor air.