HOLCUS.—(1) A spikelet of H. lanatus, magnified; (2) the same displayed to show the two flowers, the lower perfect and awnless, the upper staminate and awned.

EXPLANATION OF PLATE XIII.

HIEROCHLOA.—(1) A spikelet of H. borealis, enlarged; (2) the same displayed, the flowers separated from the empty glumes, the two lateral ones with 3 stamens and no pistil, the middle or terminal one with a pistil and only 2 stamens.

ANTHOXANTHUM—(1) The spike-like inflorescence of A. odoratum; (2) a spikelet magnified; (3) another with the parts displayed, the flowers raised from the lower empty glumes, the lateral glumes empty and awned, the terminal flower perfect and diandrous.

PHALARIS.—(1) A spikelet of P. arundinacea, enlarged, (2) the empty glumes, and a perfect flower with a hairy rudiment on each side of it.

MILIUM.—(1) Portion of the panicle of M. effusum; (2) a closed spikelet, magnified; and (3) the same displayed.

AMPHICARPUM.—(1) A spikelet from the panicle of A. Purshii, magnified; (2) the same, with the parts displayed; and (3) a radical (fertile) spikelet, enlarged.

PASPALUM.—(1) Inflorescence of P. læve; (2) a closed spikelet, enlarged; (3) the same with the parts displayed.