ANGIOSPERM CLASSIFICATION

Sanjeet kumar

ANGIOSPERM CLASSIFICATION

Historically a number of schemes have been produced. Bentham & Hooker’s Genera Plantarum (1862-1883) . comprising 200 families and 7,569 genera . pre-dated the publication of Charles Darwin.s Origin of Species.

The Angiosperm Phylogeny Group (APG): Systematic research over the past 150 years has changed our view of plant classification, especially in the last 10 years, when major advances in DNA sequencing have provided a completely new avenue of approach. Numerous classifications and schemes have been published: Hutchinson (328 families), Cronquist (388), Takhtajan (592) Dahlgren (477), Thorne (454) Brummitt (445), and Reveal (612), each differ in the recognition of families and the overall scheme. As a result, families, orders and sub-classes are not comparable between any of these systems. Molecular studies are by no means final, and, contrary to what many reference books and journals might imply, a modern synthesis is far from stabilised. However, a consensus is now beginning to emerge. The combined work of many scientists under an umbrella grouping known as the Angiosperm Phylogeny Group (APG) has produced the rudiments of an agreed evolutionary tree.

BENTHAM & HOOKER CLASSIFICATION

1. DICOTYLEDONS . 2 cotyledons, Exogenous growth.

 1.1. POLYPETALAE . petals separate

    1) THALAMIFLORAE . Sepals, Petals and Stamens all attached to receptacle.

       

a) Ranales . Gynoecium apocarpous.

1. RANUNCULACEAE; 2. DILLENIACEAE; 3. CALYCANTHACEAE;

4. MAGNOLIACEAE; 5. ANNONACEAE; 6. MENISPERMACEAE; 7. BERBERIDACEAE;

8. NYMPHACEAE.

b) Parietales . Parietal placentation. [NOT Natural. Convergent evolution:

Papaveraceae close to Ranales; remainder scattered amongst Rosids]

9. SARRACENIACEAE; 10. PAPAVERACEAE; 11. CRUCIFERAE; 12. CAPPARACEAE;

13. RESEDACEAE; 14. CISTACEAE; 15. VIOLACEAE; 16. CANELLACEAE;

17. BIXACEAE.

c) Polygalineae . Ovary 2-3 septate.

18. PITTOSPORACEAE; 19. TREMANDRACEAE; 20. POLYGALACEAE.

d) Caryophyllineae . Axile placentation.

21. FRANKENIACEAE; 22. CARYOPHYLLACEAE; 23. PORTULACACEAE;

24. TAMARICACEAE.

e) Guttiferales . Stamens numerous; Calyx imbricate.

25. ELATINACEAE; 26. HYPERICACEAE; 27. GUTTIFERAE; 28. THEACEAE;

29. DIPTEROCARPACEAE; 30. SARCOLAENACEAE.

f) Malvales . Stamens numerous; Calyx valvate.

31. MALVACEAE; 32. STERCULIACEAE; 33. TILIACEAE.

2) DISCIFLORAE . Ovary superior, immersed in disk of flower.

a) Geraniales . Ovule pendulous, raphe ventral.

34. LINACEAE; 35. HUMIRIACEAE; 36. MALPIGHIACEAE; 37. ZYGOPHYLLACEAE;

38. GERANIACEAE; 39. RUTACEAE; 40. SIMAROUBACEAE; 41. OCHNACEAE;

42. BURSERACEAE; 43. MELIACEAE; 44. DICHAPETALACEAE.

b) Olacales . Ovule pendulous, raphe dorsal.

45. OLACACEAE; 46. AQUIFOLIACEAE.

c) Celastrales . Ovule erect, raphe ventral.

47. CELASTRACEAE; 48. STACKHOUSIACEAE; 49. RHAMNACEAE; 50. VITACEAE.

d) Sapindales . Ovule ascending, raphe ventral to reversed.

51. SAPINDACEAE; 52. MELIOSMACEAE; 53. ANACARDIACEAE; 54. CORIARIACEAE;

55. MORINGACEAE.

3) CALYCIFLORAE . Stamens fused to Calyx of flower

a) Rosales . Ovaries separate, rarely united. [NOT Natural: Saxifragales as Eudicots,

Eurosids I, some Asterids]

56. CONNARACEAE; 57. LEGUMINOSAE; 58. ROSACEAE; 59. SAXIFRAGACEAE;

60. CRASSULACEAE; 61. DROSERACEAE; 62. HAMAMELIDACEAE; 63. BRUNIACEAE;

64. HALORAGACEAE.

b) Myrtales . Ovary syncarpous; divided into locules.[still form a natural group at the

base of the Rosids]

65. RHIZOPHORACEAE; 66. COMBRETACEAE; 67. MYRTACEAE;

68. MELASTOMATACEAE; 69. LYTHRACEAE; 70. ONAGRACEAE.

c) Passiflorales . Ovary syncarpous; Parietal placentation [more or less natural in the

Eurosids I]

72. LOASACEAE; 73. TURNERACEAE; 74. PASSIFLORACEAE; 75. CUCURBITACEAE;

76. BEGONIACEAE; 77. DATISCACEAE.

d) Ficoidales . Ovary syncarous; sub-basal placentation [the basal placentation is

critical in placing these families among the Caryophyllids]

78. CACTACEAE; 79. AIZOACEAE.

e) Umbellales . Ovary syncarpous; 1 ovule per locule. [not wholly natural; these

families belong amongst the basal Asterids]

80. UMBELLIFERAE; 81. ARALIACEAE; 82. CORNACEAE.

1.2. GAMOPETALAE . petals fused

1) INFERAE . Ovary inferior; stamen no. = petal no.

a) Rubiales . Stamens epipetalous; locules 2-many; ovules 1-many.

83. CAPRIFOLIACEAE; 84. RUBIACEAE.

b) Asterales . Stamens epipetalous; locule 1; ovule 1.

85. VALERIANACEAE; 86. DIPSACACEAE; 87. CALYCERACEAE; 88. COMPOSITAE.

c) Campanulales . Stamens free; locules 2-6; ovules many.

89. STYLIDACEAE; 90. GOODENIACEAE; 91. CAMPANULACEAE.

2) HETEROMERAE . Ovary superior; stamens opposite petals or double the petal

no.

a) Ericales . Stamens double petal no.; Ovary 2-many locules.

93. ERICACEAE; 93. CLETHRACEAE; 95. EPACRIDACEAE; 96. DIAPENSIACEAE;

97. LENNOCEAE.

b) Primulales . Stamens opposite petals; Ovary 1-locule; Axile placentation.

98. PLUMBAGINACEAE; 99. PRIMULACEAE; 100. MYRSINACEAE.

c) Ebenales . Stamens opposite petals; Few large seeds.

101. SAPOTACEAE; 102. EBENACEAE; 103. STYRACACEAE.

3) BICARPELLATAE . Ovary superior, with 2 carpels.

a) Gentianales . Corolla regular; leaves opposite.

104. OLEACEAE; 105. SALVADORACEAE; 106. APOCYNACEAE;

107. ASCLEPIADACEAE; 108. LOGANIACEAE; 109. GENTIANACEAE.

b) Polemoniales . Corolla regular; leaves alternate.

110. POLEMONIACEAE; 111. HYDROPHYLLACEAE; 112. BORAGINACEAE;

113. CONVOLVULACEAE; 114. SOLANACEAE.

c) Personiales . Corolla irregular to oblique; ovules many.

115. SCROPHULARIACEAE; 116. GLOBULARIACEAE; 117. LENTIBULARIACEAE;

119. GESNERIACEAE; 120. BIGNONIACEAE; 121. PEDALIACEAE; 122. ACANTHACEAE.

d) Lamiales . Corolla irregular to oblique; 1-2 ovules.

123. MYOPORACEAE; 125. VERBENACEAE; 126. LABIATAE; 127. PLANTAGINACEAE.

1.3. MONOCHLAMYDEAE . only 1 kind of perianth (not petals + sepals)

This division was never intended to be natural . it was merely to help identify these single-perianthed plants. Some are basal families (Aristolochia, Piper) with unusual flower structures, whilst others are highly derived, with sepals or petals lost. Engler and others appreciated this soon after the publication of Darwin’s Origin of Species.

1) Curved embryos [The curved embryos & seeds make these part of the Caryophyllids]

128. NYCTAGINACEAE; 130. AMARANTHACEAE; 131. CHENOPODIACEAE;

133. BATIDACEAE; 134. POLYGONACEAE.

2) Many-seeded aquatics (→ Caryophyllids / Palaeoherbs)

135. PODOSTEMACEAE; 136. NEPENTHACEAE; 137. RAFFLESIACEAE.

3) Microscopic seeds (→ Paleotrees/Palaeoherbs)

138. ARISTOLOCHIACEAE; 139. PIPERACEAE; 140. CHLORANTHACEAE;

141. MYRISTICACEAE; 142. MONIMIACEAE.

4) Daphnales (→ Paleotrees/Eudicots/Rosids)

143. LAURACEAE; 143. HERNANDIACEAE; 144. PROTEACEAE;

145. THYMELAEACEAE; 146. PENAEACEAE; 147. ELAEGNACEAE.

5) Achlamydosporaceae (→ Eudicots/Asterids)

148. LORANTHACEAE; 149. SANTALACEAE; 150. BALANOPHORACEAE.

6) Unisexulaes (→ Eudicots/Rosids)

151. EUPHORBIACEAE; 152. BALANOPACEAE; 153. URTICACEAE;

154. PLATANACEAE; 155. LEITNERIACEAE; 156. JUGLANDACEAE;

157. MYRICACEAE; 158. CASUARINACEAE; 159. BETULACEAE.

7) Ordines anomalus (→ Paleoherbs/Rosids)

160. SALICACEAE; 162. EMPETRACEAE; 163. CERATOPHYLLACEAE.

2. MONOCOTYLEDONS . 1 cotyledon, Endogenous growth.

1) Microscopic seeds

167. HYDROCHARITACEAE; 168. BURMANNIACEAE; 169. ORCHIDACEAE.

2) Inferior ovaries

170. ZINGIBERACEAE; 171. BROMELIACEAE; 172. HAEMODORACEAE;

173. IRIDACEAE; 174. AMARYLLIDACEAE; 175. VELLOZIACEAE;

176. DIOSCOREACEAE.

3) Corolla-like flowers

177. STEMONACEAE; 178. LILIACEAE; 179. PONTEDERIACEAE; 180. PHILYDRACEAE;

181. XYRIDACEAE; 182. MAYACACEAE; 183. COMMELINACEAE; 184. RAPATEACEAE.

4) Calyx-like flowers

185. FLAGELLARIACEAE; 186. JUNCACEAE; 187. PALMAE.

5) Perianth-less flowers

188. PANDANACEAE; 189. CYCLANTHACEAE; 190. TYPHACEAE; 191. ARACEAE;

192. LEMNACEAE.

6) Apocarpous

193. TRIURIDACEAE; 194. ALISMATACEAE; 195. JUNCAGINACEAE.

7) Glumaceous flowers

196. ERIOCAULACEAE; 197. CENTROLEPIDACEAE; 198. RESTIONACEAE;

199. CYPERACEAE; 200. GRAMINEAE.