216 
Spring Flora of Oklahoma 
Pistillate—Having pistils, and destitute of stamens. 
Pitted—Marked with small depressions or pits. 
Placenta—The ridge or surface bearing the ovules. 
Plicate—Folded like a fan. 
Plumose—Resembling a plume or feather. 
Plumule—The stem tip or bud of the embryo in a seed. 
Pollen grain—The male gametophyte of seed plants. 
Polygamous—Having perfect and uni-sexual flowers on the same in¬ 
dividual, or on different individuals of the same species. 
Polypetalous—Having several separate petals. 
Pome—A fruit with a fleshy perigynous disk adnate to the ovulary, 
as in the apples. 
Prickle—A stiff sharp-pointed outgrowth from the epidermis. 
Procumbent—Lying on the ground. 
Prostrate—Lying flat upon the ground. 
Puberulent—With very short hairs. 
Pubescent—Hairy, especially with fine and soft hairs. 
Punctate—With translucent dots or glands. 
Raceme—An elongated inflorescence with each flower on a peduncle. 
Racemose—Like a receme, or in a receme. 
Rachis—The axis of a compound leaf, spike, or raceme. 
Radiate—Radiating ; with ray-flowers. 
Ray—A marginal strap-shaped corolla as in the sunflower. 
Receptacle—The end of the flower stalk bearing the floral organs. 
Reflexed—Bent backward abruptly. 
Regular—Having the parts of each set alike in size and shape. 
Reniform—Kidney-shaped. 
Repand—With a more or less wavy margin. 
Reticulate—Arranged as a network. 
Retrorse—Directed downward or backward. 
Retuse—With a shallow notch at the end. 
Revolute—Rolled backward. 
Rhizome—An underground stem. 
Rootstock—A rhizome. 
Rostrate—With a beak. 
Rotate—With a flat round corolla; wheel-shaped. 
Rugose—W rinkled. 
Runcinate—Sharply and coarsely pinnatifid with the lobes turned 
backward. 
Runner—A prostrate lateral offshoot rooting at the nodes. 
Sagittate—Shaped like an arrow head. 
Salver-form—Applied to a corolla with a border spreading at right j 
angles to the tube. 
Saccate—Sac-shaped. 
Samara—A simple indehiscent winged fruit. 
