A B S T R A C TGoldberg, Aaron. Classification, Evolution, and Phylogeny of the Families of Dicotyledons. Smithsonzan Contributions to Botany, number 58, 314 pages, 164 figures, 2 tables, 1986. To some extent classification is subjective. Taxonomists differ in the relative importance they ascribe to particular characters and in the de ree of difference between related taxa they deem sufficient to constitute family or o r d i n 3 rank. About 1000 dicot family names have been ublished Those who have attempted a n overview of the s stem at the family level and agove in the last quarter century reco nize between 274 a n J 4 5 5 dicot families in 39 to 82 orders. I accept 334 families and orders. In Table 1 I give my ordinal allocation of the families and that of 1 1 recent authors to indicate where there is agreement and where there are differences to be resolved. I have also constructed a dendrogram to su gest relationships and degree of advancement of the orders.f have written concise, uniform descriptions of all the families of dicots, emphasizing those characters that show trends between families or occur in more than one famil .Each family is illustrated by analytical drawings of the flower, fruit, seed and usual& inflorescence. Several species are usually used to show the range of major variation within families and trends toward related families.Angiosperms probably arose from gymnosperms, so characters or character states universal in gymnosperms or considered primitive in them would also be considered primitive in angiosperms.My a proach to understanding evolutionary trends in characters is to relate them to the ecokgical factors that might be responsible for them by their selective action. T h e dicots probably originated under warm tern erate conditions favorable for growth. A character states enabling them to cope with dry and hot or colaconditions and colonize generally unfavorable re ions.A second major trend kas been from wind pollination to progressive1 better adaptation for insect pollination. T h e primitive insect pollinated dicots often xave flowers with numerous spirally arranged parts; plants having flowers with few, opposite or whorled major evolutionary trend in them has been t K e gradual develo ment of characters and parts are derived.seDarate. T h e connate and adnate conditions are derived.
A B S T R A C TI have written concise, uniform descriptions of all the families of monocots emphasizing those characters that show trends between families or occur in more than one family. Each family is illustrated by analytical drawings of the flower, fruit, seed, and usually inflorescence.Several species are usually used to show the range of major variation within families and trends toward related families.Monocots and dicots have existed concurrently for most of their history, have been subjected to many of the same ecological pressures, and consequently show similar evolutionary trends. My approach to understanding evolutionary trends in characters is to relate them to the ecological factors that might be responsible for them by their selective action. The monocots probably originated under warm temperate or subtropical conditions favorable for growth. A major evolutionary trend in them has been the gradual development of characters and character states enabling them to cope with dry and hot or cold conditions and colonize generally unfavorable habitats.A second major trend has been progressively greater specialization for insect pollination. The primitive monocots have flowers with numerous spirally arranged parts; those having fIowers with few, opposite or whorled parts are derived.The floral organs are homologous with leaves. Like leaves the parts were initially separate. The connate and adnate conditions are derived.General character states are primitive; specialized states are derived. In attempting to determine which primitive states are most primitive I considered their occurrence among the families. The fewer the families with a particular primitive state, the more primitive the state. This is important in deciding whether a family is low or high on the family tree and the position within its particular order.In accordance with the above rationale, I have constructed a table giving t h e primitive and derived states for about 85 characters. I also indicate the extent to which I consider the states reversible.To determine a family's phylogeny, it must be compared with other families considered to be close to it. In general, the more characters and character states in common, particularly uncommon ones, the more likely are the subject families to be related. All parts of the plant and many characters should be considered. If a family has more than one state of a character, the state considered primitive for the particular family should be used in attempting to determine the extant family closest to its ancestor. A descendant has at least one more derived character or character state than its ancestor.
Haptanthus is known from only a single collection despite several attempts to recollect it. Because of its unique inflorescence and flowers, and the specimen's lack of fruit, the original authors were unable to assign it to an existing family. After 12 years Nelson described it as the type of a new family, Haptanthaceae. The original authors mainly described and illustrated the gross morphology, pistil anatomy, and pollen of Haptanthus. In attempting to assign it to a family, eight familial placements were considered and reasons were given for their rejection. In the present paper additional characters of the leaf, stem, and pistil, mainly anatomical, are described and illustrated. Most of the wood characters are archaic (primitive).Haptanthus has a suite of characters indicating that it is probably wind-pollinated. Consideration of all the characters studied to date, and examination of additional literature and herbarium specimens of several families, enable us to suggest Flacourtiaceae and Euphorbiaceae as the closest relatives of Haptanthaceae. Recently, Flacourtiaceae has been suggested by another author. Key characters of the three families are compared in a table.
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