Root Burn: Condition which describes an African Violet that is receiving urea nitrogen. More information.
Root Interception: One of three processes by which soil nutrients become available to African Violets and other plants. Root interception describes the movement of roots through the soil as they grow, thus bringing them into contact with essential elements. Also see Diffusion and Mass Flow.
Root Interface: Any point on the roots where they come in contact with the soil.
Root Knot: Also called gall. A swollen mass of abnormal growth which appears on the roots. On African Violets, root knots are very often caused by Root Nematodes.
Root Knot Nematodes: See Root Nematodes.
Root Mealy Bugs: Rhizoecus americanus. A common species of Mealy Bug known to feed on the roots of African Violets. See Soil Mealy Bugs.
Root Nematodes: Meloidogyne incognita. Also called Root Knot Nematodes. Microscopic, unsegmented worms known to feed within the roots of African Violets. Root Nematodes enter through the pores or wounds in the roots. Their feeding activity causes swollen masses, known as root knots, to develop on the roots. In almost all cases, Root Nematodes are fatal. More information.
Root Rot: On African Violets, a condition caused by a fungus called Cylindrocarpon. The fungus thrives when the soil is wet and soggy. Root Rot will cause an otherwise healthy-looking plant to topple over at the base. More information.
Root Zone: See Rhizosphere.
Rootball: Also called soilball. Collectively, the roots and the soil which surrounds them. On African Violets, the rootball is formed by the pot in which it is grown.
Rootbound: Also called potbound. Condition which describes an African Violet that has outgrown its pot. When an African Violet is rootbound, its roots will grow out and around the rootball, thus indicating that it is time to repot. More information.
Rooted Clump: A group of plantlets growing out of the same leaf cutting.
Rooting A Sucker: Method of propagation. Method involves removing a sucker from a parent plant and placing it in a rooting medium until it has fully developed its own root system.
Rooting Box: Sometimes called heating box. A box sometimes used during leaf propagation to regulate the temperature of the rooting medium, i.e., a temperature of 70 to 75 degrees F.
Rooting Hormone: A natural hormone, called auxin, which helps promote the growth of roots on leaf cuttings. Also see Rooting Powder.
Rooting Medium: pl. rooting media. Sometimes called leaf start mix or starter mix. A potting medium especially formulated for rooting leaf cuttings. Also used for rooting peduncle cuttings and suckers. When propagating from a tissue culture, the rooting medium is agar.
Rooting Powder: A powder containing rooting hormones to help promote the growth of roots on leaf cuttings. Rooting powders may also contain additional ingredients, such as a fungicide to prevent Damping Off.
Rootlet: Tiny root still in the process of developing. Also see Radicle.
Roots: The part of African Violets and other plants which radiates from the main stem and grows beneath the soil line. While also providing support for the plant, the most important function of roots is to absorb water and essential elements, which become available by three processes: diffusion, mass flow and root interception.
Rosalie: Rhapsodie variety. Medium, standard African Violet (4-inch pot size) with single, bi-color flowers. Flowers are pink and white. Leaves are medium green. Introduced 1995. Improved 1998. (AVSA Reg. No. 8352) More information.
Rose: Rhapsodie variety. Medium, standard African Violet (4-inch pot size) with double, two-tone pink flowers and dark green leaves (red reverse). Introduced 1991. (AVSA Reg. No. 7503) More information.
Rose Quartz: Optimara super miniature variety. See Little Rose Quartz.
Rosenquartz: Holtkamp variety (Europe). Super miniature African Violet (2-inch pot size) with semi-double, pink flowers and medium green leaves. Available in the U.S. as Little Rose Quartz.
Rosette: Growth habit. Also called rosulate or Biedermeier-style. Describes an African Violet with a single crown from which the leaves radiate evenly. With very few exceptions, all commercial varieties are grown as rosettes.
Rosulate: Growth habit. See Rosette.
Round: Leaf type. Describes an African Violet leaf which is nearly circular in shape. Contrast with Ovate and Longifolia.
Roxanna: Rhapsodie variety. Large, standard African Violet (4-inch pot size) with semi-double, bi-color flowers. Flowers are white with red rays. Leaves are dark green. Introduced 1987. (AVSA Reg. No. 6619) More information.
Ruby (1): Rhapsodie variety. Medium, standard African Violet (4-inch pot size) with double, dark red flowers and dark green leaves. More information.
Ruby (2): Optimara super miniature variety. See Little Ruby.
Ruched: Leaf type. See Ruffled.
Ruffled (1): Bloom type. See Frilled.
Ruffled (2): Leaf type. Also called curly, fluted, frilled, lacy, ruched, undulate or wavy. Describes an African Violet leaf with a ruffled edge. A tightly ruffled edge is often called curly or lacy. A loosely ruffled edge is often called undulate or wavy.
Rumba: Optimara variety belonging to the Little Dancer series. Compact African Violet (3-inch pot size) with frilled, bi-color flowers and medium green leaves. Introduced 1998. Improved 1999. More information.
Rumiko: Optimara variety. Medium, standard African Violet (4-inch pot size) with single, dark blue flowers and medium green leaves. Introduced 1992. More information.
Rupicola: See Saintpaulia rupicola.
Ruth: Rhapsodie variety. Large, standard African Violet (4-inch pot size) with semi-double, bi-color flowers. Flowers are white with a burgundy center. Leaves are medium green. Introduced 1997. More information.
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