=Larva= (plural =larvae=): the young or immature form of an insect. =Larval=: belonging to larva. =Layer=: to propagate plants by a method similar to cutting, but differing from cutting in that the young plant takes root before it is separated from the parent plant. =Legume=: a plant belonging to the family of the pea, clover, and bean; that is, having a flower of similar structure. =Lichen=: a kind of flowerless plant that grows on stones, trees, boards, etc. =Loam=: an earthy mixture of clay and sand with organic matter. =Magnesia=: an earthy white substance somewhat similar to lime. =Magnify=: to make a thing larger in fact or in appearance; to enlarge the appearance of a thing so that the parts may be seen more easily. =Membrane=: a thin layer or fold of animal or vegetable matter. =Mildew=: a cobwebby growth of fungi on diseased or decaying things. =Mold=: see mildew. =Mulch=: a covering of straw, leaves, or like substances over the roots of plants to protect them from heat, drought, etc., and to preserve moisture. =Nectar=: a sweetish substance in blossoms of flowers from which bees make honey. =Nitrate=: a readily usable form of nitrogen. The most common nitrate is saltpeter. =Nitrogen=: a chemical element, one of the most important and most expensive plant foods. It exists in fertilizers, in ammonia, in nitrates, and in organic matter. =Nodule=: a little knot or bump. =Nutrient=: any substance which nourishes or promotes growth. =Organic matter=: substances made through the growth of plants or animals. =Ovary=: the particular part of the pistil that bears the immature seed. =Ovipositor=: the organ with which an insect deposits its eggs. =Oxygen=: a gas present in the air and necessary to breathing. =Particle=: any very small part of a body. =Perennial=: living through several years. All trees are perennial. =Petal=: a single leaf of the corolla. =Phosphoric acid=: an important plant food occurring in bones and rock phosphates. =Pistil=: the part of the blossom that contains the immature seeds. =Pollen=: the powdery substance borne by the stamen of the flower. It is necessary to seed production. =Pollination=: the act of carrying pollen from stamens to pistils. It is usually done by the wind or by insects. =Porosity=: the state of having small openings or passages between the particles of matter. =Potash=: an important part of plant foods. The chief source of potash is kainit, muriate of potash, sulphate of potash, wood ashes, and cotton-hull ashes. =Propagate=: to cause plants or animals to increase in number. =Protein=: the name of a group of substances containing nitrogen. It is one of the most important of feeding stuffs. =Pruning=: trimming or cutting parts that are not needed or that are injurious. =Pulverize=: to reduce to a dustlike state. =Pupa=: an insect in the stage of its life that comes just before the adult condition.