Flowering Plants: Smartweeds to Hazelnuts

Introduction

Introduction Flowering plants that form two "seed leaves," or cotyledons, when the seed germinates are called dicotyledons, or dicots. These far exceed the number of species of monocots, or flowering plants that produce a single "seed leaf" upon germination. This is the fifth volume of The Illustrated Flora of Illinois to be devoted to the dicots of Illinois. The system of classification adopted for The Illustrated Flora of Illinois was proposed by Thorne in 1968. This system is a marked departure from the more familiar system of Engler and Prantl. This latter system, which is still followed in most regional floras, is outof -date and does not reflect the vast information recently gained from the study ofcytology, biochemistry, anatomy, and embryology. Since the arrangement of orders and families proposed by Thorne is unfamiliar to many, an outline of the orders and families of flowering plants known to occur in Illinois is presented. Those names in boldface are described in this volume of The Illustrated Flora of Illinois. Order Annonales Family Magnoliaceae Family Annonaceae Family Calycanthaceae Family Aristolochiaceae Family Lauraceae Family Saururaceae Order Berberidales Family Menispermaceae Family Ranunculaceae Family Berberidaceae Family Papaveraceae Order Nymphaeales Family Nymphaeaceae Family Ceratophyllaceae Order Sarraceniales Family Sarraceniaceae Ordm' Theales Family Aquifoliaceae Family Hypericaceae1 Family Elatinaceae Family Ericaceae Order Ebenales Family Ebenaceae Family Styracaceae Family Sapotaceae Order Primulales Family Primulaceae Order Cistales Family Violaceae Family Cistaceae Family PassiHoraceae Family Cucurbitaceae Family Loasaceae Order Salicales Family Salicaceae Order Tamaricales Family Tamaricaceae Order Capparidales Family Capparidaceae Family Resedaceae Family Brassicaceae 2 / SMARTWEEDS TO HAZELNUTS Order Malvales Family Sterculiaceae Family Tiliaceae Family Malvaceae Order Urticales Family Ulmaceae Family Moraceae Family Urticaceae Order Rhamnales Family Rhamnaceae Family Elaeagnaceae Order Euphorbiales Family Thymelaeaceae Family Euphorbiaceae Order Solanales Family Solanaceae Family Convolvulaceae Family Polemoniaceae Order Campanulales Family Campanulaceae Order Santalales Family Celastraceae Family Santalaceae Family Loranthaceae Order Oleales Family Oleaceae Order Geraniales Family Linaceae Family Zygophyllaceae Family Oxalidaceae Family Geraniaceae Family Balsaminaceae Family Limnanthaceae Family Polygalaceae Order Rutales Family Rutaceae Family Simaroubaceae Family Anacardiaceae Family Sapindaceae Family Aceraceae Family Hippocastanaceae Family Juglandaceae Order Myricales Family Myricaceae Order Chenopodiales Family Phytolaccaceae Family Nyctaginaceae Family Aizoaceae Family Cactaceae Family Portulacaceae Family Chenopodiaceae Family Amaranthaceae Family Caryophyllaceae Family Polygonaceae Order Hamamelidales Family Hamamelidaceae Family Platanaceae Order Fagales Family Fagaceae Family Betulaceae Family Corylaceae Order Rosales Family Rosaceae Family Fabaceae Family Crassulaceae Family Saxifragaceae Family Droseraceae Family Staphyleaceae Order Myrtales Family Lythraceae Family Melastomaceae Family Onagraceae Order Gentianales Family Loganiaceae Family Rubiaceae Family Apocynaceae Family Asclepiadaceae2 Family Gentianaceae Family Menyanthaceae Order Bignoniales Family Bignoniaceae Family Martyniaceae Family Scrophulariaceae Family Plantaginaceae Family Orobanchaceae Family Lentibulariaceae Family Acanthaceae Order Cornales Family Vitaceae Family Nyssaceae Family Cornaceae Family Haloragidaceae Family Hippuridaceae Family Araliaceae Family Apiaceae3 Order Dipsacales Family Caprifoliaceae Family Adoxaceae Family Valerianaceae Family Dipsacaceae Introduction I 3 Order Lamiales Family Hydrophyllaceae Family Boraginaceae Family Verbenaceae Family Phrymataceae1 Family CaIIitrichaceae Family Lamiaceae Order Asterales Family Asteraceae 'Called Clusiaceae by Thorne (1968). 2Included in Apocynaceae by Thorne (1968). 3Included in Araliaceae by Thorne (1968). 'Included in Verbenaceae by Thorne (1968). Included in this volume is one family, the Polygonaceae, from the large order Chenopodiales, and two orders in their entirety, the Hamamelidales, with two families, and the Fagales, with three families . Eight other families of the order Chenopodiales will be in other volumes of The Illustrated Flora of Illinois. Since only a small number of dieot families are treated in this book, no general key to the dicot families has been provided. The reader is invited to use my companion book, Guide to the Vascular Flora of Illinois. Revised and Enlarged Edition (1g86), for keys to all families of flowering plants in Illinois. The Polygonaceae is the only family in this book in which at least the staminate flowers are not borne in asexual apetalous spikes known as catkins. They are an advanced member ofthe order Chenopodiales , according to Thorne (1968). Cronquist (1g81), on the other hand, considers the Polygonaceae to be the sole family in the order Polygonales. In the Cronquist system, however, both the Polygonaceae and the other Illinois families of Chenopodiales, according to Thorne, are placed in the subclass Caryophyllidae. The Hamamelidales, containing the Hamamelidaceae and the Platanaceae, and the Fagales, containing the Fagaceae, the Betulaceae , and the Corylaceae are included by Cronquist (1g81) in the subclass Hamamelidae. From a phylogenetic point of view, all the families treated in this volume are considered to be advanced families, that is, they have characteristics which generally are not...