Dichotomous Key/Cycas

CycadKingSago.jpg Plantae Cycadophyta Cycadopsida Cycadales Key to the species of Cycas: Cycas CYC1: Ovules coated with hair. CYC2: Ovules lacking hair. CYC1 Cycas taitungensis: Pinnae flat Cycas revoluta: Pinnae rolled near the tip CYC2 CYC3: Expanded portion of Megasporophyll leaf with closely parallel toothlike projections. CYC4: Expanded portion of megasporophyll leaf without closely parallel toothlike projections. CYC3 CYC5: Male cones are stiff and rigid CYC6: Male cones are soft CYC4 CYC10: Spongy tissue present in seeds. CYC11: Spongy tissue not present in seeds. CYC5 CYC7: Hard seed coat is ribbed. Cycas panzhihuaensis: Hard seed coat is not ribbed. CYC6 CYC8: Soft seed coat is not fibrous; hard seed coat is studded with wart-like projections CYC9: Soft seed coat is fibrous; hard seed coat is smooth. CYC7 Cycas curranii: Pinnae over 6 millimeters wide; seeds over 40 millimeters long. Cycas wadei: Pinnae less than 6 millimeters wide; seeds less than 40 millimeters long. CYC8 CYC14: Top of megasporophyll spine much longer and wider than lateral spines CYC15: Top of megasporophyll spine similar to lateral spines CYC9 Cycas lindstromii: Male cones less than 5 centimeters in diameter; Stems underground CYC17: Male cones over 5 centimeters in diameter; stem rises at least partially above ground. CYC10 CYC20: Seeds have a wing on the tip CYC21: Seeds do not have an obvious wing on the tip CYC11 CYC12: Hard seed coat has a fibrous layer CYC13: Hard seed coat does not have a fibrous layer. CYC12 Cycas beddomei: Pinnae less than 5 millimeters wide CYC27: Pinnae over 5 millimeters wide. CYC13 CYC37: Basal pinnae gradually reducing in size CYC38: Basal pinnae not gradually reducing in size CYC14 CYC49: Pinnae less than 11 millimeters wide. CYC50: Pinnae over 11 millimeters wide CYC15 CYC54: Pinnae simple CYC55: Pinnae dichotomously divided CYC16 Cycas chamaoensis: Male cones rounded and tapering from the middle toward each end; Spindle-shaped CYC63: Male cones elliptical or oval-shaped CYC17 Cycas hongheensis: Leaves have a distinct longitudinal ridge and covered with hair. CYC19: Leaves mostly flat and at least the top is without hair. CYC18 Cycas siamensis: Basal pinnae reducing to spines CYC64: Basal pinnae not reducing to spines. CYC19 CYC16: Phelloderm smooth CYC18: Phelloderm corky CYC20 Cycas rumphii: Megasporophyll lateral spines are small bumps CYC22: Megasporophyll lateral spines distinct CYC21 CYC23: Pinnae are broad, very glossy, and bright green CYC24: Pinnae are slightly glossy; Pinnae are bluish when new CYC22 Cycas micronesica: Apical spine is less than 15 millimeters long CYC25: Apical spine is over 15 millimeters long CYC23 Cycas edentata: Plants found in the Philippines. Cycas litoralis: Plants found in Thailand CYC24 Cycas thouarsii: Fewer broad, short cataphylls present. Plants of Madagascar Cycas zeylanica: Numerous thin, long cataphylls present. Plants of Sri Lanka. CYC25 Cycas boubainvilleana: Pinnae over 12 millimeters wide CYC26: Pinnae less than 12 millimeters wide. CYC26 Cycas falcata: Petioles usually spiny. Cycas seemannii: Petioles without spines, or with few spines. CYC27 CYC28: Pinnae less than ten millimeters wide CYC29: Pinnae over ten millimeters wide. CYC28 CYC30: Lateral megasporophyll teeth less than four millimeters long. CYC31: Lateral megasporophyll teeth over four millimeters long. CYC29 Cycas pranburiensis: Petioles lacking spikes or bristles CYC32: Petioles have spines or bristles CYC30 Cycas circinalis: Megasporophyll lamina 75 to 100 millimeters long. Plants of India Cycas nathorstii: Megasporophyll lamina 40 to 70 millimeters long. Plants of Sri Lanka CYC31 Cycas chamberlainii: Lateral spines on megasporophyll lamina over ten millimeters long. CYC33: Lateral spins on megasporophyll lamina less than 10 millimeters long. CYC32 Cycas macrocarpa: Lateral teeth of megasporophyll over seven millimeters long. CYC34: Lateral teeth of megasporophyll less than seven millimeters long. CYC33 Cycas riuminiana: Plants of the Philippines Cycas spherica: Plants of India CYC34 Cycas apoa: Lamina lacking lateral spines CYC35: Lamina has distinct lateral spines or teeth. CYC35 Cycas javana: Lamina thin and tapering toward the tip. CYC36: Lamina egg-shaped. CYC36 Cycas inermis: Stems 1 to 4 meters tall; 8 to 14 centimeters in diameter; Petiole is 60 to 80 centimeters long. Cycas scratchleyana: Stems over 4 meters tall; 12 to 20 centimeters in diameter; Petiole is 20 to 70 centimeters long. CYC37 CYC39: Lateral megasporophyll teeth large; Basal pinnae reducing to spines. CYC40: Lateral megasporophyll teeth small; Basal pinnae not reducing to spines. CYC38 CYC41: Hypodermis present; Leaf edges recurved. CYC42: Hypodermis absent; Leaf edges flat. CYC39 Cycas basaltica: Leaves are flat CYC67: Leaves are keeled CYC40 CYC68: Pinnae edges flat or recurved; Pinnae more than five millimeters wide. CYC69: Pinnae rolled backward or downward; Pinnae less than five millimeters wide. CYC41 CYC43: Hypodermis continuous; Leaves grey or blue. CYC44: Hypodermis interrupted; Leaves green. CYC42 Cycas canalis: New leaves glaucous blue CYC70: New leaves green or bluish green CYC43 CYC45: Leaves strongly glaucous; Male cones oval-shaped. CYC46: Leaves not glaucous, or only slightly; Male cones large and spherical. CYC44 CYC47: Spines and/or bristles present on cataphylls CYC48: Spines and/or bristles not present on cataphylls CYC45 CYC76: Pinnae edges rolled backward or downward; Pinnae less than four millimeters wide. CYC77: Pinnae edges flat or recurved, but not rolled backward or downward; Pinnae over four millimeters wide. CYC46 Cycas angulata: Pinnae are less than six millimeters wide. Cycas brunnea: Pinnae are over six millimeters wide. CYC47 Cycas megacarpa: Leaves are keeled over 135 degrees. CYC75: Leaves are flat, or at least keeled less than 135 degrees. CYC48 CYC79: Cataphylls and crown densely orange and wooly. CYC80: Cataphylls and crown gray or white. CYC49 Cycas hainanensis: Seeds relatively large CYC51: Seeds relatively small CYC50 Cycas taiwaniana: Twelve to thirty leaves in crown Cycas tanqingii: Four to seven leaves in crown CYC51 CYC52: Plants relatively large CYC53: Plants relatively small CYC52 Cycas tropophylla: Leaves keeled Cycas ferrunginea: Leaves flat CYC53 Cycas chanfjiangensis Cycas miquelii CYC54 CYC56: Microsporophylls coming to a short, abrupt point. CYC57: Microsporophylls rounded CYC55 CYC58: Pinnae dichotomously divided two to three times. CYC59: Pinnae pinnately divided and dichotomously divided more than three times. CYC56 unfinished Cycas chevalieri: Cycas fugax: Cycas hoabinhensis: CYC57 Cycas diannanensis: Cataphylls long and rigid. CYC60: Cataphylls short and soft. CYC58 Cycas micholitzii: Leaves 110 to 240 centimeters long and moderately keeled (inserted at 90-120 degrees on rachis) Cycas multifrondis: Leaves 200 to 500 centimeters long and flat to slightly keeled (inserted at 120-180 degrees on rachis) CYC59 Cycas debaoensis: Megasporophylls are 12-14 centimeters long Cycas multipinnata: Megasporophylls are 7-11 centimeters long CYC60 CYC61: Male cones are small and narrow CYC62: Male cones are large CYC61 unfinished Cycas balansae Cycas brachycantha Cycas simplicipinna CYC62 unfinished Cycas collina Cycas dolichophylla Cycas guizhouensis Cycas segmentifida Cycas yunnanensis CYC63 Cycas pectinata: Has long apical microsporophyll spine. CYC65: Has a short apical microsporophyll spine. CYC64 Cycas nongnoochiae: Male cones small CYC66: Male cones medium to small. CYC65 unfinished Cycas clivicola Cycas elongata Cycas tansachana CYC66 unfinished Cycas condaoensis Cycas pachypoda CYC67 Cycas furfuracea: Pinnae margins flat or recurved; pinnae are over five millimeters wide Cycas pruinosa: Pinnae margins are rolled backward or downward; pinnae are less than five millimeters wide. CYC68 Cycas arnhemica: New growth with mostly brown or orange trichomes. Cycas maconochiei: New growth with mostly white or grey trichomes. CYC69 Cycas arenicola: Pinnae four to seven millimeters wide; 180-270 pinnae present. Cycas calcicola: Pinnae two to four millimeters wide; 200-400 pinnae present. CYC70 Cycas conferta: Pinnae the same color throughout and have stomata on upper and lower surfaces. CYC71: Pinnae more or less different colors throughout and only have stomata on one side. CYC71 CYC72: Cataphylls pale brown and hairy CYC73: Cataphylls orange and wooly CYC72 Cycas orientis: Midrib more prominent below than above. CYC74: Midrib equally prominent above and below. CYC73 Cycas armstrongii: Stems less than twelve centimeters in diameter. Cycas lane-poolei: Stems over twelve centimeters in diameter. CYC74 unfinished Cycas papuana Cycas xipholepis CYC75 Cycas media: Pinnae are less than nine millimeters wide; Cataphylls are persistent. Cycas silvestris: Pinnae are over nine millimeters wide; Cataphylls are deciduous. CYC76 Cycas cairnsiana: Cataphylls soft and short. Cycas desolata: Cataphylls sharply pointed and long. CYC77 Cycas couttsiana: Main growth mostly gray or white trichomes. CYC78: Main growth mostly orange or brown trichomes. CYC78 Cycas ophiolitica: Pinnae six to eight millimeters wide; Leaves keeled at 80-120 degrees. Cycas platyphylla: Pinnae four to six millimeters wide; Leaves keeled at 45-60 degrees. CYC79 Cycas campestris: Lateral spines of megasporophyll lamina over 8 millimeters long. CYC81: Lateral spines of megasporophyll lamina less than 8 millimeters long CYC80 Cycas semota: Megasporophylls 18 to 25 centimeters long; Apex 15 to 35 millimeters wide and not dilated. Cycas tuckeri: Megasporophylls 10 to 15 centimeters long; Apex 35 to 50 millimeters wide and dilated. CYC81 unfinished Cycas badensis Cycas schumanniana Cycas yorkiana