gonophore

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

• noun A reproductive structure that forms on a hydrozoan polyp.

from The Century Dictionary.

• noun In botany, a prolongation of the axis of a flower, bearing the stamens and pistil above the perianth, as in Gynandropsis.
• noun In zoology, one of the generative buds or receptacles of the reproductive elements in the hydrozoans or zoöphytes.
• noun In physiology, any accessory organ of generation which serves to convey or detain the generative products of tho gonads or essential sexual organs of either sex. Oviducts and spermiducts of all kinds, as well as uteri, seminal vesicles, etc., are gonophores.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) A sexual zooid produced as a medusoid bud upon a hydroid, sometimes becoming a free hydromedusa, sometimes remaining attached. See hydroidea, and Illusts. of athecata, campanularian, and gonosome.
• noun (Bot.) A lengthened receptacle, bearing the stamens and carpels in a conspicuous manner.

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

• noun botany An elongated receptacle above the corolla to elevate the stamens and carpels.
• noun zoology A medusoid bud on a hydroid.