MANUAL OF THE GRASSES OF THE UNITED STATES 



993 



Monoecious. Unisexual, the two kinds of 

 flowers on the same plant, as in Zea and 

 Zizania. 



Mucro. A minute awn or excurrent midnerve 

 of an organ. Mucronate. Provided with a 

 mucro. 



Navicular. Boat-shaped. Shaped like the 

 bow of a canoe. Applied especially to the 

 tip of blades. 



Nerve. The vascular veins (mostly longi- 

 tudinal) of the blades, glumes, and 

 lemmas. 



Neuter. Without stamens or pistils. Said of 

 florets or spikelets. 



Nodding. Inclined somewhat from the vert- 

 ical. Said of panicles. 



Node. The joint of a culm. 



Nodulose. Roughened by minute knots. 



06-. A prefix meaning inversely, as obovate. 



Oblong. Longer than wide, with parallel 

 sides, but not so long as linear. Applied 

 also to panicles and other parts, having in 

 mind a longitudinal section. 



Obsolete. Almost wanting. Applied to organs 

 usually present. 



Obtuse. Rounded at the apex. Contrasted 

 with acute. 



Open. Loose. Said of panicles. Opposite of 

 dense or compact. 



Oval. Broadly elliptic. 



Ovate. The shape of the longitudinal section 

 of an egg, broadest below the middle. 



Ovoid. An egg-shaped solid. 



Palea. The inner bract of a floret. 



Panicle. An inflorescence with a main axis 

 and subdivided branches. It may be com- 

 pact and spikelike (Phleum pratense) or 

 open (Avena saliva). 



Papery. See chartaceous. 



Papilla. A minute nipple-shaped projection. 



Papillose. Bearing papillae. Papillose-pilose. 

 Bearing stiff hairs arising from papillae. 



Pappus. In grasses mentioned under Pap- 

 pophorum, referring to the awns as form- 

 ing a pappuslike crown, similar to the 

 pappus in certain species of Compositae. 



Pectinate. Comblike. Used especially with 

 some species of Bouteloua where the spike- 

 lets are set close together, parallel and 

 divergent from the rachis like the teeth of 

 a comb. 



Pedicel. The stalk of a spikelet. Pedicellate. 

 Having a pedicel. Opposed to sessile. 



Peduncle. The stalk or stem of an inflores- 

 cence. Peduncled. Having a peduncle. 



Pendent. Hanging down. 



Perennial. Lasting more than 1 year. Ap- 

 plied to -grasses in which the underground 

 parts last more than 1 year; and to woody 

 culms to distinguish them from those 

 which die to the ground (herbaceous) even 

 though the underground parts are peren- 

 nial. 



Perfect. Applied to flowers having both 

 stamens and pistil. 



Pericarp. The ripened walls of the ovary 

 when it becomes a fruit. 



Persistent. Remaining attached, either after 



other parts have been shed, or for a con- 

 siderable period. The paleas of certain 

 species of Eragrostis persist after the fall 

 of the lemmas. Also used as the opposite 

 of deciduous. 



Petiole. The stalk of a leaf blade. Used with 

 the leaves of many bamboos and with 

 some other broadleaved species in which 

 the blade contracts into a petiole. Petio- 

 late. Having a petiole. 



Pilose. Pubescent with soft straight hairs. 



Pistillate. Applied to flowers bearing pistils 

 only and to an inflorescence or a plant 

 with pistillate flowers. 



Pitted. Marked with small depressions or 

 pits. Applied to the fruit (fertile lemma) of 

 certain species of Olyra. Also applied to 

 the pinhole depression in the glume of 

 certain species of Andropogoneae. 



Plicate. Folded in plaits lengthwise as the 

 blades of Setaria sect. Ptycophyllum. ' 



Plumbeous. Lead-colored, greenish drab, as 

 the spikelets of Eragrostis cilianensis. 



Plumose. Feathered, having fine hairs on 

 each side. Said chiefly of awns and slender 

 teeth. 



Proliferous. Bearing vegetative buds or 

 bulblets in the inflorescence. Compare 

 bulblets. 



Pruinose. Having a waxy powdery secretion 

 on the surface. Having a more pronounced 

 bloom than when glaucous. 



Puberulent. Diminutive of pubescent. Min- 

 utely pubescent. 



Pubescent. Covered with hairs. Applied 

 especially when the hairs are short and 

 soft. Pubescence. A hairy covering. 



Pulvinus. The swelling at the base of the 

 branches of some panicles which cause 

 them to spread. 



Pustulose. Blistery, furnished with pustules 

 or irregularly raised pimples, as in the 

 spikelets of Panicum angustifolium. Not 

 as definitely roughened as papillose. 



Pyramidal. Pyramid-shaped. Applied some- 

 times to panicles that are actually conical. 



Pyriform. Pear-shaped. Obovoid with atten- 

 uate base. Applied to the shape of spike- 

 lets. 



Raceme. An inflorescence in which the spike- 

 lets are pediceled on a rachis. Racemose. 

 In racemes. 



Rachilla. A small rachis. Applied especially 

 to the axis of a spikelet. 



Rachis. The axis of a spike or raceme. 



Reticulate. In a network. Applied especially 

 to the cross-veining on some spikelets, as 

 Panicum fasciculatum. 



Retrorse. Pointing backward, as the hairs on 

 the sheaths of certain species of Bromus. 



Revolute. Turned or rolled backward from 

 both edges. Said chiefly of blades. 



Rhizome. An underground stem; rootstock. 

 The rhizomes of grasses are usually slender 

 and creeping. They bear scales at the 

 nodes, the scales sometimes remote and 

 inconspicuous (Poa pratensis), sometimes 

 imbricate and prominent (Spartina). 



