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734. Explanation of the Plates.

Arrenatherum.-A spikelet of A. avenaceum displayed and magnified: 1, the glumes; 2, the flowers, the lower one staminate only, the next perfect, and the third a rudiment.

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

Tab VII.

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

Anthoxanthum.-The spike-like inflorescence of A. odoratum (1); a spikelet magnified (2); another with the parts displayed, the flowers raised from the glumes, the lateral ones neutral, each of a single and awned palea, the middle one perfect and diandrous (3).

Phalaris.-A spikelet of P. arundinacea enlarged (1); the glumes and the perfect flower with a hairy rudiment on each side of it (2).

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

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

Paspalum.-Inflorescenc eof P. laeve (1); a closed spikelet, enlarged (2); the same with the parts displayed (3).

Panicum.-Part of a spike of P. (Digitaria) sanguinale (1); one of its spikelets magnified (2); the same with the parts displayed (3); in this the lower flower is neutral and of a single palea. A spikelet of P. capillare, magnified (4); and the same displayed (5); the lower flower of a single palea. A spikelet of P. clandestinum, magnified (6), and the same displayed (7); the lower flower neutral, of two paleae. A spikelet of P. virgatum, magnified (8); the same displayed (9); the lower flower of two paleae and staminate.

Setaria.-A magnified spikelet of S. glauca, with the accompanying cluster of bristles (1); the spikelet displayed, showing the neutral lower flower of two paleae and the perfect flower (2).

Tab VIII.

Cenchrus.-A spiny involucre of C. tribuloides, in flower, enlarged (1); the longitudinal section of the same (2); a spikelet detached and displayed (3): the stigmas should belong to the right-hand or upper flower; the land-hand, or lower flower is only staminate.

Tripsacum.-Piece of the spike (of the natural size), pistillate below, staminate above (1); a longitudinal section of one of the pistillate spikelets (2); a pistillate spikelet with its parts displayed (3); a staminate (2-flowered) spikelet, with its parts displayed (4).

Erianthus.-Part of the hairy inflorescence with two spikelets of E. alopecuroides, enlarged (1); one of the spikelets displayed (2).

Andropogon.-Small portion of the spike of A. furcatus, enlarged with one fertile and awned spikelet, and one staminate and awnless spikelet (1); the fertile spikelet (2), and the staminate spikelet (3) displayed.

Sorghum.-A fertile spikelet of S. nutans, enlarged, with a sterile pedicel on each side (1); the spikelet displayed (2).