Q:

Identify this indoor plant with strange stem-like leaves

It appears that this plant branches multiple times from the base of its stem; however, I'm not sure if the base stems are from one organism. It becomes yellowish in color at the tip each stem-like leaves; one node can branch 3-4 leaves at a time. 
Additional information:
As for the specimen location- I am currently living in Japan and this plant was bought as a gift for me. It probably is imported from other countries since it doesn't seem to be native here. For maintenance; I was told to just cut the tip of the leaves if it began to fade in color and die; and water the plant at least once a week.

A:

Looks like a Pencil Tree (Euphorbia tirucalli), sometimes called "pencil plant", "pencil cactus" or "milkbush." This "leafless-looking" plant is not actually a cactus, but actually a "Euphorbia" (i.e., member of the Euphorbiaceae family), and should present a white "milky" liquid latex when broken.

CAUTION: THIS IS A POISONOUS PLANT [See symptoms here].

Description: A succulent, spineless shrub with round, green branches; leaves clustered at the tip of the branches and soon dropping

Although it eventually can grow into a small-sized tree in its natural habitat, this plant is found more commonly as a medium-sized house plant or landscaping "shrub."

Range: Tropical Africa and India

Euphorbia tirucalli is very well adapted to semi-arid conditions, but also occurs in both dry and moist forest, savanna and shrub land, and withstands salt stress associated with coastal conditions, but no frost. It occurs from sea-level up to 2500 m altitude. It grows well on a wide variety of light-textured, neutral to acidic soils. It is commonly associated with human settlements and becomes naturalized rapidly. It is locally common and often occurs in groups. [Source].

