Identification of Costus Species Dave Skinner 1 Dr. P. J. M. Maas University of Utrecht Flora Neotropica • Monograph No. 8 – 1972 • Monograph No. 18 – 1977 – updated key Notes on Asiatic Costoideae – 1979 Notes on New World Zing. – 1990 • With wife, Dr. Hiltje Maas – 3 new species described Two New Costa Rican Species – 1997 • P.J.M. & Hiltje Maas 2 Other References Flore Du Gabon – Jean Koechlin - 1964 • African species (20 species described) • Written in French, includes key Flora of Australia – Rosemary Smith – 1987 Dr. Chelsea D. Specht • Molecular Phylogeny of Costaceae - 2001 • Post-doctoral work at the Smithsonian • Soon-to-be-published Reclassification of Costus 3 Family Costaceae Currently 4 genera Costus Monocostus Dimerocostus Tapeinochilos 70 species 1 species 2 (4) species 18 species Americas South Central and New Guinea Africa America South Indonesia Asia America Australia Australia 4 Genus Costus 5 subgenera Eucostus Cadalvena Paracostus Epicostus Metacostus (Costus) Examples Examples Examples Examples Examples C. barbatus C. cuspidatus C. paradoxus C. tappenbeckianus C. lateriflorus C. speciosus C. subsessilis C. englerianus C. arabicus C. curcumoides C. globosus C. lanceolatus C. spicatus C. pictus C. dubius 5 New World Costus Identification Keys by Maas Identification Hierarchy I. Subgenus – (Cadalvena vs. Eucostus) Subgenus Eucostus (Costus) II a. Labellum – spreading (Section I, Melittophilus – Costus) vs. tubular (Section II, Ornithophilus) II b. Bracts – appendaged (Group I) vs. not appendaged (Group II) 6 Example of tubular flowers Section Ornithophilus 7 Example of spreading labellums Section Melittophilus 8 Example of appendaged bracts Group I 9 Example of non- appendaged bracts Group II 10 Bract Color 11 Bract Margins 12 # of Flowers per Bract 13 Calyx Length 14 Bracteole Shape and Length 15 Ligule Length & Lobes 16 Terminal vs. Basal Bloomers 17 African Costus Identification Keys by Koechlin Identification Hierarchy I. Stems - Stemless (C. spectabilis) vs. upright or creeping II. Leaves - Single leaf (C. englerianus) vs. many leaves III. Inflorescence - Radical (basal) vs. Lateral vs. Terminal IV. Height (basal bloomers) – over 1 meter vs. under 1 meter IV. Appendages (terminal bloomers) – with or without V. Other characters 1. Ligules 2. Single flower vs. two flowers per bract 3. Raised ring on ligule 18 Generally NOT used for identification Presence of hairs (“fuzziness”) on leaves and pseudostems Coloration of leaves Shape of leaves 19 Costus that have been incorrectly identified in US horticulture 20 21 Costus lacerus Often incorrectly identified as Costus speciosus 22 Costus lacerus Has fibrous margins and blunt ends to the bracts. 23 Costus speciosus Pungent bracts, margins entire 24 25 26 Costus productus Sold in horticulture as Costus curvibracteatus 27 Bracts are appendaged Costus productus 28 Edge of bract appendage is curved inwards on this plant. Description of C. curvibracteatus has the apex of the bracts “slightly curved outwards”. 29 Costus productus - ligules 30 Costus ‘Maroon Chalice’ is a form of Costus productus 31 32 Costus scaber Sold in horticulture as Costus spicatus 33 34 Comparison of Costus spicatus (hort.) with Costus scaber (Smithsonian specimen) – the flower parts were identical and matched Maas’ description of Costus scaber. 35 Costus cylindricus (syn. spicatus) As identified at the Smithsonian, #2002-127 36 37 Costus arabicus ‘variegatus’ Sold in horticulture as Costus amazonicus ‘variegatus’ 38 C. arabicus = snow white flowers, tinged purple. C. amazonicus = yellow corolla, yellow labellum, dark red-striped lateral lobes, yellow with red margined middle lobe, Costus amazonicus Costus arabicus reddish stamen ‘Variegatus’ Specimen from (horticulture) Smithsonian 39 Branching Stems 40 Cordate leaf base 41 New and/or unidentified Costus species 42 Probably a natural hybrid of Costus spiralis X Costus arabicus 43 Costus ‘Tropicais’ 44 Costus ‘El Whiskey’ 45 Costus ‘El Whiskey’ 46 Possibly Costus jururanus 47 Some other Costus species 48 Costus allenii ‘Santa Fe form’ 49 Costus barbatus 50 Costus chartaceus 51 Costus claviger 52 Costus comosus 53 Costus cuspidatus 54 Costus dubius 55 Costus erythrophyllus 56 Costus erythrothyrsus 57 Costus globosus 58 Costus laevis 59 Costus lasius 60 Costus lucanusianus 61 Costus lucanusianus (yellow form) 62 Costus maculatus 63 Costus malortieanus 64 Costus mosaicus 65 Costus osae 66 Costus pictus 67 Costus pulverulentus 68 Costus speciosus ‘Variegatus 69 Costus spiralis 70 Costus stenophilus 71 Costus subsessillis 72 Costus talbotii 73 Costus tappenbeckianus 74 Costus varzearum 75 Costus villisissimus 76 Costus vinosus 77 Costus woodsonii 78 www.gingersrus.com www.gingersrus.com/test/identifier.php [email protected] Thanks – Dave Skinner 79 .