bamboo vs gramineous plant

bamboo and gramineous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
bamboo	Yes	No	No	No
gramineous plant	Yes	No	No	No

As nouns, gramineous plant is a hypernym of bamboo; that is, gramineous plant is a word with a broader meaning than bamboo:

bamboo: woody tropical grass having hollow woody stems; mature canes used for construction and furniture
gramineous plant: cosmopolitan herbaceous or woody plants with hollow jointed stems and long narrow leaves

Other hypernyms of bamboo include graminaceous plant.

bamboo (noun)	gramineous plant (noun)
woody tropical grass having hollow woody stems; mature canes used for construction and furniture	cosmopolitan herbaceous or woody plants with hollow jointed stems and long narrow leaves
the hard woody stems of bamboo plants; used in construction and crafts and fishing poles