microgametophyte

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The male gametophyte that arises from a microspore of a heterosporous plant. In seed plants, the microgametophyte is contained in the pollen grain.

from The Century Dictionary.

• noun A male gametophyte when the sexes are diœciously separated.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology Any gametophyte that develops from a microspore
• noun biology A male gametophyte

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the male gametophyte produced by a microspore