Skill India

innaeus in his Species Plantarum in 1753.Linnaeus’ six species of Azalea were Azalea indica,
A. pontica, A. lutea, A. viscosa, A. lapponica and A. procumbens (now Kalmia procumbens),
which he distinguished from Rhododendron by having five stamens, as opposed to ten. As new
species of what are now considered Rhododendron were discovered, they were assigned to
separate genera if they seemed to differ significantly from the type species. For instance
Rhodora (Linnaeus 1763) for Rhododendron canadense, Vireya (Blume 1826).Most of the
Balfourian series are represented by Sleumer as subsections, though some appear as sections
or even subgenera. Sleumer based his system on the relationship of the flower buds to the leaf
buds, habitat, flower structure, and whether the leaves were lepidote or non-lepidote. While
Sleumer’s work was widely accepted, many in the United States and the United Kingdom
continued to use the simpler Balfourian system of the Edinburgh group

Sleumer’s system underwent many revisions by others, predominantly the Edinburgh group in
their continuing Royal Botanic Garden Edinburgh notes. Cullen of the Edinburgh group, placing
more emphasis on the lepidote characteristics of the leaves, united all of the lepidote species
into subgenus Rhododendron, including four of Sleumer’s subgenera (Rhododendron,
Pseudoazalea, Pseudorhodorastrum, Rhodorastrum).moved to subgenus Azaleastrum, section
Sciadorhodion. Similarly the single species in monotypic subgenus Mumeazalea
(Rhododendron semibarbatum) was placed in the new section Tsutsusi, subgenus Azaleastrum.
Genus Menziesa (9 species) was also added to section Sciadorhodion. The remaining small
subgenus Therorhodion with its two species was left intact. Thus two subgenera, Hymenanthes
and Azaleastrum were expanded at the expense of four subgenera that were eliminated,
although Azaleastrum lost one section (Choniastrum) as a new subgenus, since it was a distinct
subclade in a. In all, Hymenanthes increased from one to two sections, while Azaleastrum, by
losing one section and gaining two increased from two to three sections.Terminology from the
Sleumer (1949) system is frequently found in older literature, with five subgenera and is as
follows;
Subgenus Lepidorrhodium Koehne: Lepidotes. 3 sections
Subgenus Eurhododendron Maxim.: Elipidotes.
Subgenus Pseudanthodendron Sleumer: Deciduous azaleas. 3 sections
Subgenus Anthodendron Rehder & Wilson: Evergreen azaleas. 3 sections
Subgenus Azaleastrum Planch.: 4 sections
The largest of these is subgenus Rhododendron, containing nearly half of all known species and
all of the lepidote species.
Subgenus Rhododendron L.: Small leaf or lepidotes (scales on the underside of the leaves). 3
sections, 462 species, type species: Rhododendron ferrugineum.
Subgenus Hymenanthes (Blume) K.Koch: Large leaf or elepidotes (without scales). 1 section,
224 species, type Rhododendron degronianum.
Subgenus Pentanthera (G. Don) Pojarkova: Deciduous azaleas. 4 sections, 23 species, type
Rhododendron luteum.
Subgenus Tsutsusi (Sweet) Pojarkova: Evergreen azaleas. 2 sections, 80 species, type
Rhododendron indicum.
Subgenus Azaleastrum Planch.: 2 sections, 16 species, type Rhododendron ovatum.
Subgenus Candidastrum Franch.: 1 species, Rhododendron albiflorum.
Subgenus Mumeazalea (Sleumer) W.R. Philipson & M.N. Philipson: 1 species, Rhododendron
semibarbatum.
Subgenus Therorhodion (Maxim.) A. Gray: 2 species (Rhododendron camtschaticum,
Rhododendron redowskianun).This division was based on a number of what were thought to be
key morphological characteristics. These included the position of the inflorescence buds
(terminal or lateral), whether lepidote or elepidote, deciduousness of leaves, and whether new
foliage was derived from axils from previous year’s shoots or the lowest scaly leaves .A number
of insects either target rhododendrons or will opportunistically attack them. Rhododendron
borers and various weevils are major pests of rhododendrons, and many caterpillars will
preferentially devour them.
Rhododendron species are used as food plants by the larvae (caterpillars) of some butterflies
and moths; see List of Lepidoptera that feed on rhododendrons.Rhododendron bud blast, a
fungal condition that causes buds to turn brown and dry before they can open, is caused by the
fungus Pycnostysanus azaleae, which may be brought to the plant by the rhododendron
leafhopper, Graphocephala fennahi.They can self-propagate by sending up shoots from the
roots. Sometimes an attached branch that has drooped to the ground will root in damp mulch,
and the resulting rooted plant then can be cut off the parent rhododendron.Rhododendrons are
grown commercially in many areas for sale, and are occasionally collected in the wild, a practice
now rare in most areas. Larger commercial growers often ship long distances; in the United
States, most of them are on the west coast (Oregon, Washington state and California).
Large-scale commercial growing often selects for different characteristics than hobbyist growers
might want, such as resistance to root rot when overwatered, ability to be forced into budding
early, ease of rooting or other propagation, and saleability.