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RHS Online: Gardening for All

Classification of genera

Genera including a large number of species or with many cultivars are often subdivided into informal horiticultural classifications or formal cultivar groups in the case of Clematis and Tulipa.

The breeding of new cultivars is sometimes limited to hybrids between closely-related species, thus for Saxifraga and Primula, the cultivars are allocated to the sections given in the infrageneric treatments cited.


(s-p) Self-pollinating


(C) Cane-like
(R) Rex Cultorum
(S) Semperflorens Cultorum
(T) x tuberhybrida (Tuberous)

(By the National Chrysanthemum Society)

(1) Indoor Large (Exhibition)
(2) Indoor Medium (Exhibition)
(3a) Indoor Incurved: Large-flowered
(3b) Indoor Incurved: Medium-flowered
(3c) Indoor Incurved: Small-flowered
(4a) Indoor Reflexed: Large-flowered
(4b) Indoor Reflexed: Medium-flowered
(4c) Indoor Reflexed: Small-flowered
(5a) Indoor Intermediate: Large-flowered
(5b) Indoor Intermediate: Medium-flowered
(5c) Indoor Intermediate: Small-flowered
(6a) Indoor Anemone: Large-flowered
(6b) Indoor Anemone: Medium-flowered
(6c) Indoor Anemone: Small-flowered
(7a) Indoor Single: Large-flowered
(7b) Indoor Single: Medium-flowered
(7c) Indoor Single: Small-flowered
(8a) Indoor True Pompon
(8b) Indoor Semi-pompon
(9a) Indoor Spray: Anemone
(9b) Indoor Spray: Pompon
(9c) Indoor Spray: Reflexed
(9d) Indoor Spray: Single
(9e) Indoor Spray: Intermediate
(9f) Indoor Spray: Spider, Quill, Spoon or Any Other Type
(10a) Indoor, Spider
(10b) Indoor, Quill
(10c) Indoor, Spoon
(11) Any Other Indoor Type
(12a) Indoor, Charm
(12b) Indoor, Cascade
(13a) October-flowering Incurved: Large-flowered
(13b) October-flowering Incurved: Medium-flowered
(13c) October-flowering Incurved: Small-flowered
(14a) October-flowering Reflexed: Large-flowered
(14b) October-flowering Reflexed: Medium-flowered
(14c) October-flowering Reflexed: Small-flowered
(15a) October-flowering Intermediate: Large-flowered
(15b) October-flowering Intermediate: Medium-flowered
(15c) October-flowered Intermediate: Small-flowered
(16) October-flowering Large
(17a) October-flowering Single: Large-flowered
(17b) October-flowering Single: Medium-flowered
(17c) October-flowering Single: Small-flowered
(18a) October-flowering Pompon: True Pompon
(18b) October-flowering Pompon: Semi-pompon
(19a) October-flowering Spray: Anemone
(19b) October-flowering Spray: Pompon
(19c) October-flowering Spray: Reflexed
(19d) October-flowering Spray: Single
(19e) October-flowering Spray: Intermediate
(19f ) October-flowering Spray: Spider, Quill, Spoon or Any Other Type
(20) Any Other October-flowering Type
(22a) Charm: Anemone
(22b) Charm: Pompon
(22c) Charm: Reflexed
(22d) Charm: Single
(22e) Charm: Intermediate
(22f ) Charm: Spider, Quill, Spoon or Any Other Type
(23a) Early-flowering Outdoor Incurved: Large-flowered
(23b) Early-flowering Outdoor Incurved: Medium-flowered
(23c) Early-flowering Outdoor Incurved: Small-flowered
(24a) Early-flowering Outdoor Reflexed: Large-flowered
(24b) Early-flowering Outdoor Reflexed: Medium-flowered
(24c) Early-flowering Outdoor Reflexed: Small-flowered
(25a) Early-flowering Outdoor Intermediate: Large-flowered
(25b) Early-flowering Outdoor Intermediate: Medium-flowered
(25c) Early-flowering Outdoor Intermediate: Small-flowered
(26a) Early-flowering Outdoor Anemone: Large-flowered
(26b) Early-flowering Outdoor Anemone: Medium-flowered
(27a) Early-flowering Outdoor Single: Large-flowered
(27b) Early-flowering Outdoor Single: Medium-flowered
(28a) Early-flowering Outdoor Pompon: True Pompon
(28b) Early-flowering Outdoor Pompon: Semi-pompon
(29a) Early-flowering Outdoor Spray: Anemone
(29b) Early-flowering Outdoor Spray: Pompon
(29c) Early-flowering Outdoor Spray: Reflexed
(29d) Early-flowering Outdoor Spray: Single
(29e) Early-flowering Outdoor Spray: Intermediate
(29f ) Early-flowering Outdoor Spray: Spider, Quill, Spoon or Any Other Type
(29K) Early-flowering Outdoor Spray: Korean
(29Rub) Early-flowering Outdoor Spray: Rubellum
(30) Any Other Early-flowering Outdoor Type

Cultivar Groups as per Matthews, V (2002) The International Clematis Register & Checklist 2002, Royal Horticultural Society, London

(A) Atragene Group
(Ar) Armandii Group
(C) Cirrhosa Group
(EL) Early Large-flowered Group
(F) Flammula Group
(Fo) Forsteri Group
(H) Heracleifolia Group
(I) Integrifolia Group
(LL) Late Large-flowered Group
(M) Montana Group
(T) Texensis Group
(Ta) Tangutica Group
(V) Viorna Group
(Vb) Vitalba Group
(Vt) Viticella Group

(By the National Dahlia Society with corresponding numerical classification according to the Royal Horticultural Society’s International Register)

(Sin) 1 Single
(Anem) 2 Anemone-flowered
(Col) 3 Collerette
(WL) 4 Waterlily (unassigned)
(LWL) 4B Waterlily, Large
(MWL) 4C Waterlily, Medium
(SWL) 4D Waterlily, Small
(MinWL) 4E Waterlily, Miniature
(D) 5 Decorative (unassigned)
(GD) 5A Decorative, Giant
(LD) 5B Decorative, Large
(MD) 5C Decorative, Medium
(SD) 5D Decorative, Small
(MinD) 5E Decorative, Miniature
(SBa) 6A Small Ball
(MinBa) 6B Miniature Ball
(Pom) 7 Pompon
(C) 8 Cactus (unassigned)
(GC) 8A Cactus, Giant
(LC) 8B Cactus, Large
(MC) 8C Cactus, Medium
(SC) 8D Cactus, Small
(MinC) 8E Cactus, Miniature
(S-c) 9 Semi-cactus (unassigned)
(GS-c) 9A Semi-cactus, Giant
(LS-c) 9B Semi-cactus, Large
(MS-c) 9C Semi-cactus, Medium
(SS-c) 9D Semi-cactus, Small
(MinS-c) 9E Semi-cactus, Miniature
(Misc) 10 Miscellaneous
(O) Orchid-flowering (in combination)
(B) Botanical (in combination)
(DwB) Dwarf Bedding (in combination)
(Fim) Fimbriated (in combination)
(Lil) Lilliput (in combination)

(By the Royal Horticultural Society)

(p) Pink
(p,a) Annual Pink
(pf ) Perpetual-flowering Carnation
(b) Border Carnation
(M) Malmaison Carnation


(B) Black (Vitis), Blackcurrant (Ribes)
(Ball) Ballerina (Malus)
(C) Culinary (Malus, Prunus, Pyrus, Ribes)
(Cider) Cider (Malus)
(D) Dessert (Malus, Prunus, Pyrus, Ribes)
(F) Fruit
(G) Glasshouse (Vitis)
(O) Outdoor (Vitis)
(P) Pinkcurrant (Ribes)
(Perry) Perry (Pyrus)
(R) Red (Vitis), Redcurrant (Ribes)
(S) Seedless (Citrus, Vitis)
(W) White (Vitis), Whitecurrant (Ribes)


(B) Butterfly
(E) Exotic
(G) Giant
(L) Large
(M) Medium
(Min) Miniature
(N) Nanus
(P) Primulinus
(S) Small
(Tub) Tubergenii

Hydrangea macrophylla

(H) Hortensia
(L) Lacecap

(By the American Iris Society)

(AB) Arilbred
(BB) Border Bearded
(Cal-Sib) Series Californicae x Series Sibiricae
(CH) Californian Hybrid
(DB) Dwarf Bearded (not assigned)
(Dut) Dutch
(IB) Intermediate Bearded
(La) Louisiana Hybrid
(MDB) Miniature Dwarf Bearded
(MTB) Miniature Tall Bearded
(SDB) Standard Dwarf Bearded
(Sino-Sib) Series Sibiricae, chromosome number 2n=40
(Spuria) Spuria
(TB) Tall Bearded

(Classification according to The International Lily Register (ed. 3, 1982) with amendments from Supp. 10 (1992), Royal Horticultural Society)

(I) Early-flowering Asiatic Hybrids derived from L. amabile, L. bulbiferum, L. cernuum, L. concolor, L. davidii, L. x hollandicum, L. lancifolium, L. leichtlinii, L. x maculatum and L. pumilum
(Ia) Upright flowers, borne singly or in an umbel
(Ib) Outward-facing flowers
(Ic) Pendant flowers
(II) Hybrids of Martagon type, one parent having been a form of L. hansonii or L. martagon
(III) Hybrids from L. candidum, L. chalcedonicum and other related European species (excluding L. martagon)
(IV) Hybrids of American species
(V) Hybrids derived from L. formosanum and L. longiflorum
(VI) Hybrid Trumpet Lilies and Aurelian hybrids from Asiatic species, including L. henryi but excluding those from L. auratum, L. japonicum, L. rubellum and L. speciosum
(VIa) Plants with trumpet-shaped flowers
(VIb) Plants with bowl-shaped flowers
(VIc) Plants with flat flowers (or only the tips recurved)
(VId) Plants with recurved flowers
(VII) Hybrids of Far Eastern species as L. auratum, L. japonicum, L. rubellum and L. speciosum (Oriental Hybrids)
(VIIa) Plants with trumpet-shaped flowers
(VIIb) Plants with bowl-shaped flowers
(VIIc) Plants with flat flowers
(VIId) Plants with recurved flowers
(VIII) All hybrids not in another division
(IX) All species and their varieties and forms

Malus (see Fruit)

(By the Royal Horticultural Society, revised 1998)

(1) Trumpet
(2) Large-cupped
(3) Small-cupped
(4) Double
(5) Triandrus
(6) Cyclamineus
(7) Jonquilla and Apodanthus
(8) Tazetta
(9) Poeticus
(10) Bulbocodium
(11a) Split-corona: Collar
(11b) Split-corona: Papillon
(12) Miscellaneous
(13) Species


(H) Hardy
(D) Day-blooming
(N) Night-blooming
(T) Tropical


(S) Shrubby


(A) Angel
(C) Coloured Foliage (in combination)
(Ca) Cactus (in combination)
(d) Double (in combination)
(Dec) Decorative
(Dw) Dwarf
(DwI) Dwarf Ivy-leaved
(Fr) Frutetorum
(I) Ivy-leaved
(Min) Miniature
(MinI) Miniature Ivy-leaved
(R) Regal
(Sc) Scented-leaved
(St) Stellar (in combination)
(T) Tulip (in combination)
(U) Unique
(Z) Zonal

(Classification by Section as per W W Smith & Forrest (1928) and W W Smith & Fletcher (1941- 49))

(1) Amethystina
(2) Auricula
(3) Bullatae
(4) Candelabra
(5) Capitatae
(6) Carolinella
(7) Cortusoides
(8) Cuneifolia
(9) Denticulata
(10) Dryadifolia
(11) Farinosae
(12) Floribundae
(13) Grandis
(14) Malacoides
(15) Malvacea
(16) Minutissimae
(17) Muscarioides
(18) Nivales
(19) Obconica
(20) Parryi
(21) Petiolares
(22) Pinnatae
(23) Pycnoloba
(24) Reinii
(25) Rotundifolia
(26) Sikkimensis
(27) Sinenses
(28) Soldanelloideae
(29) Souliei
(30) Vernales
(A) Alpine Auricula
(B) Border Auricula
(Poly) Polyanthus
(Prim) Primrose
(S) Show Auricula
(St) Striped Auricula

Prunus (See Fruit)

Pyrus (See Fruit)


(A) Azalea (deciduous, species or unclassified hybrid)
(Ad) Azaleodendron
(EA) Evergreen azalea
(G) Ghent azalea (deciduous)
(K) Knap Hill or Exbury azalea (deciduous)
(M) Mollis azalea (deciduous)
(O) Occidentalis azalea (deciduous)
(R) Rustica azalea (deciduous)
(V) Vireya rhododendron
(Vs) Viscosa azalea (deciduous)

Ribes (See Fruit)


(A) Alba
(Bb) Bourbon
(Bs) Boursault
(Ce) Centifolia
(Ch) China
(Cl) Climbing (in combination)
(D) Damask
(DPo) Damask Portland
(F) Floribunda or Cluster-flowered
(G) Gallica
(Ga) Garnette
(GC) Ground Cover
(HM) Hybrid Musk
(HP) Hybrid Perpetual
(HT) Hybrid Tea or Large-flowered
(Min) Miniature
(Mo) Moss (in combination)
(N) Noisette
(Patio) Patio, Miniature Floribunda or Dwarf Cluster-flowered
(Poly) Polyantha
(PiH) Pimpinellifolia hybrid (Hybrid Scots Briar)
(Ra) Rambler
(RH) Rubiginosa hybrid (Hybrid Sweet Briar)
(Ru) Rugosa
(S) Shrub
(T) Tea

(Classification by Section from Gornall, R J (1987). Botanical Journal of the Linnean Society, 95(4): 273-292)

(1) Ciliatae
(2) Cymbalaria
(3) Merkianae
(4) Micranthes
(5) Irregulares
(6) Heterisia
(7) Porphyrion
(8) Ligulatae
(9) Xanthizoon
(10) Trachyphyllum
(11) Gymnopera
(12) Cotylea
(13) Odontophyllae
(14) Mesogyne
(15) Saxifraga

(Classification by Cultivar Group from Classified List and International Register of Tulip Names by Koninklijke Algemeene Vereening voor Bloembollenculture 1996)

(1) Single Early Group
(2) Double Early Group
(3) Triumph Group
(4) Darwinhybrid Group
(5) Single Late Group (including Darwin Group and Cottage Group)
(6) Lily-flowered Group
(7) Fringed Group
(8) Viridiflora Group
(9) Rembrandt Group
(10) Parrot Group
(11) Double Late Group
(12) Kaufmanniana Group
(13) Fosteriana Group
(14) Greigii Group
(15) Miscellaneous


(G) Species and hybrids considered by some botanists to belong to the separate genus Glandularia.


(C) Cornuta Hybrid
(dVt) Double Violet
(ExVa) Exhibition Viola
(FP) Fancy Pansy
(PVt) Parma Violet
(SP) Show Pansy
(T) Tricolor
(Va) Viola
(Vt) Violet
(Vtta) Violetta

Vitis (See Fruit) RHS PLANT Finder