Raceme
Special terms
Type of inflorescence.
Glossary of terms
A reference section with categories and short explanations.
Radial spines
Cactus grower terms
Spines located on the periphery of the areole.
Radicle emergence
Cactus grower terms
The emergence of the embryonic root through the rupture of the testa during seed germination.
Radish-like roots
Cactus grower terms
(Not napiform) thickening of the taproot.
Ramp
Landscape terms
A slightly inclined plane that replaces a staircase.
Range
Orchid terms
The territory within which a particular species, genus, or family of plants naturally occurs.
Rarity
Cactus grower terms
Rarity, a rare specimen; an exceptionally rare plant both in terms of being held in collections and of occurring in natural conditions.
Receptacle
Cactus grower terms
The upper expanded part of the pedicel.
Receptaculum
Cactus grower terms
(Lat. term receptaculum - receptacle - the axis of the flower on which the sepals, petals, stamens, carpels are arranged) - a term used by many cactologists to denote the receptacle specific to all higher cacti.
Recessive
Cactus grower terms
(From Latin recessus - retreat, removal) - an allele whose phenotypic expression in the heterozygote is masked by the dominant allele.
Reciprocal crosses
Cactus grower terms
(From Latin reciprocus - mutual) - two crosses characterized by a mutually opposite combination of the trait under study and the sex of the forms participating in these crosses.
Reduction
Cactus grower terms
Decrease in size of plant organs or tissues.
Regeneration
Cactus grower terms
Restoration by a living organism of lost body parts.
Rejuvenating a violet
African violet terms
Violet rosettes need to be rejuvenated every 2-3 years; during that time the rosette develops a bare stem. Rejuvenation is done by cutting off the top part of the rosette (the crown) and re-rooting it in water. During rejuvenation new root…
Rejuvenating a violet
Special terms
Violet rosettes require mandatory rejuvenation every 2–3 years; during that time the rosette develops a bare stem. Rejuvenation is carried out by cutting off the upper part of the rosette (the crown) and re-rooting it in water. When rejuve…
Relative humidity
Cactus grower terms
Expressed as the ratio of the concentration of water vapor contained in the air to its maximum saturated state at a given air temperature. As temperature increases, relative humidity decreases.
Relative humidity
Garden terms
The amount of water in the air compared to the saturation level at the same temperature; expressed as a percentage.
Relict plants
Cactus grower terms
Dying out; surviving in small numbers.
Repens
Bonsai terms
Creeping
Replantation
Cactus grower terms
Engraftment (survival) of a detached organ.
Respiration
Garden terms
The process by which the cells and tissues of a plant take up oxygen, resulting in the release of energy required for growth and development.
Reticulatus
Bonsai terms
Cobwebby
Rhizoctoniosis
Cactus grower terms
Fungal disease of cacti.
Rhizome
Orchid terms
Also: rhizome – rhizome - a subterranean, more or less perennial shoot of perennial herbaceous plants, as well as shrubs, serving for the storage of reserve substances, vegetative renewal and reproduction. It differs from a root by the pre…
Rhizome
Special terms
An underground modified shoot with reduced scale-like leaves. In some plants, a rhizome is formed aboveground or half submerged in the substrate.
Roboku: (roboku)
Bonsai terms
Ancient, antique bonsai.
Robustus
Bonsai terms
Robust
Rock garden
Landscape terms
A garden or park area where ornamental plants are combined with rocks.
Rock garden (alpinarium)
Landscape terms
A rock garden that reflects the beauty of a mountain landscape and its flora. It is characterized by the combination of low-growing alpine plants with rocks and water. Rock gardens first appeared in English landscape gardens in the 18th ce…
Rock wall garden
Landscape terms
A decorative structure made of stacked stones in the form of slopes or retaining walls. Planting soil is pressed into the cracks between the stones and ornamental herbaceous plants are planted there (xerophytes, less often inhabitants of m…
Root collar
Cactus grower terms
The point where the roots transition into the stem.
Root collar
Special terms
The boundary between the root and the stem.
Root cutting
Garden terms
A section of root (rhizome) used to propagate a plant.
Root hairs
Cactus grower terms
Absorbing, dying off as the root grows.
Root parasites
Cactus grower terms
Plant pests that damage roots.
Root primordia
Cactus grower terms
Groups of cells from which new roots develop.
Root suckers
Cactus grower terms
Shoots arising from adventitious buds.
Root system
Cactus grower terms
The collection of a plant's underground roots. The taproot system has a primary root and lateral roots; the fibrous or fasciculate system — the primary root is weakly developed or dies early, and adventitious roots form a cluster, a fascic…
Rooted cutting
African violet terms
A leaf cutting that has produced roots.
Rooted cutting
Special terms
Leaf cutting that has developed roots.