A monograph of the genus Evolvulus BY S.J. van Ooststroom (Printed June 1934) CONTENTS. Page I. Introduction 1 II. General part 4 1. History of the genus 4 2. Morphology 5 3. Relationships S 4. Geographical distribution 11 5. Use 14 III. Taxonomical part 17 Evolvulus L 19 Key to the sections 20 Section I. Alsinoidei Meissn. emend 22 Subsect. 1. Pedunculati v. Ooststr 22 Subsect. 2. Epedunculati v. Ooststr 101 Section II. Linoidei Meissn. 163 Section III. Paniculati Peter 172 Section IV. Passerinoidei Meissn 175 Section V. Phyllostachyi Meissn. 199 Section VI. Involucrati v. Ooststr 223 Section VII. Lagopodini Meissn 234 Doubtful and little-known species 244 Excluded species 244 List of collectors’ numbers 247 Index 263 I. INTRODUCTION. number The great difficulties arising in the identification of a which of plants belonging to the genus Evolvulus, plants were found in several recent collections of Convolvulaceae and were kindly entrusted to me for study, induced me to submit this further It how the genus to a examination. soon proved great literature and the herbaria. prevailing confusion was, both in in Various species were again and again wrongly interpreted and this especially concerns those which had been described by the older authors. Thanks to the invaluable help of a great number of herbaria I was in a position to bring about some order in the Still unsolved. A close genus. numerous questions remain study of living material, preferably on the habitat itself, will often be of value here. I had of material at great a great quantity my the disposal, kindly lent me by following herbaria. (These her- indicated the taxonomical the abbreviations baria are in part by in parentheses.) Botanischer Garten und Botanisches Museum, Berlin— Dahlem. (B) ’s Lands Plantentuin, Buitenzorg, Java. (Bog) Institut de Botanique et Herbier Boissier, Genève. (Boiss) Jardin Botanique de l’Etat, Bruxelles. (Br) Institute Biologico de Defeza Agricola e Animal, São Paulo. (Bu) Universitetets Botaniske Museum, Copenhagen. (C) Royal Botanic Gardens, Sibpur, Calcutta. (Calc) Conservatoire et Jardin Botaniques de la Ville, Herbier de Candolle, Genève. (DC) id., Herbier Delessert, Genève. (Del) Field Museum of Natural History, Department of Botany, Chicago. (F) 1 2 Botanisches Institut und Botanischer Garten der Universität, Göttingen. (G) Gray Herbarium, Harvard University, Cambridge, Mass., U.S.A. (Gr) Hortus Botanicus en Botanisch Laboratorium van de Rijksuniversiteit, Groningen. (Gro) Botanisches Institut der Universität, Halle a. Saale. (H) Herbarium E. Hassler, San Bernardino, Paraguay. (Hassl) Royal Botanic Gardens, Kew, Surrey. (K) Rijks Herbarium, Leiden. (L) Botanischer Garten (Glawnij botanitscheski sad), Leningrad. (Len) Linnean Society of London, London. (Linn) Botanisches Museum, München. (M) British Museum (Natural History), London. (NH) New York Botanical Garden. (NY) Museum national d’Histoire naturelle, Herbier et Laboratoire de Botanique, Phanérogamie, Paris. (P) Jardim Botanico, Rio de Janeiro. (R) Naturhistoriska Riksmuseet, Stockholm. (S) Botanic Garden, Singapore. (Sing) Musee du Congo Belge, Tervueren. (T) Botanisch Museum en Herbarium van de Rijks- universiteit, Utrecht. (U) United States National Herbarium, Smithsonian Institution, Washington, D.C., U.S.A. (US) Naturhistorisches Museum, Botanische Abteilung, Wien. (V) Here I wish best thanks the directors of these to express my to for their the herbaria great assistance and especially to directors and staff of the herbaria and libraries I have personally visited, viz. the “Jardin Botanique de l’Etat”, Brussels, the Royal Bo- tanic Gardens, Kew, the Linnean Society of London, the British Museum of Natural History, London, the “Muséum national d’Histoire naturelle”, Paris and the “Musée du Congo Belge”, Tervueren. Further the director and staff of the my gratitude to 3 “Rijks Herbarium” at Leyden, the collections and library of which I have so often and most thanks consulted, finally my sincere to Professor Dr. A. Pulle, Director of the “Botanisch Museum en Herbarium van de Rijks Universiteit” at Utrecht, under whose direction this work was completed. His great assistance, his continual interest in the work and his advice in the composition thereof have been of inestimable value to me. II. GENERAL PART. 1. HISTORY OF THE GENUS. The Evolvulus 1 first Linnaeus genus ) was described by in the second edition of his Species Plantarum. 2 ) Linnaeus distinguished 5 species here; three of the five species also occur in the first edition of the Species Plantarum (1753), but under the name of Convolvulus. They are C. nummularius, C. alsinoides and C. tridentatus. The which Linnaeus of the description gave genus in 1762 was rather incomplete, and the important characteristic, that of the two 2-cleft styles, is not mentioned in it. A better diagnosis follows in the Genera Plantarum, ed. 6 (1764). Here there is a fairly exact description of the styles; “styli 4, capillares, divergentes, longit. staminum. Stigmata simplicia”. To the species Linnaeus described from India, Burman3 ) added in 1768 two others, neither of which, however, belonged the 4 to genus. Lamarck’s Encyclopedic ) gives a summary of the species known in 1789, 8 in number, 3 of these, however, do Persoon 5 not belong to the genus. ) gives 9 species, two of which' were described by Ruiz and P a v o n in their Flora A Peruviana. general view of the Australian forms was given by Robert Brown 6 ) in 1810, of the Asiatic forms by Roxburgh 7 ) in 1832. Poiret 8 ) in the Supplement to Lamarck’s of Encyclopedic gives a summary the species known in 1813. These are indeed all Evolvulus species. After Poiret 7 = to not in ) derived from evolvo unroll, twining as Convolvulus. 2 ed. 2 391. ) Linnaeus, Spec. Plant, (1762) p. 3 ) Burman, Flora Indica (1768) p. 76. 4 Lamarck, Meth. 573. ) Encycl. (1789) p. 5 ) Persoon, Syn. I (1805) p. 288. 6 ) Brown, Rob., Prodr. FI. Nov. Holl. ed. 1 (1810) p. 489, 7 ) Roxburgh, Flora Indica II (1832) p. 105. 8 Poiret in Lam. Ill 458. ) Encycl. Suppl. (1813) p. 5 the number of species described gradually increases. The sum- 1 in his Convolvulaceae Rariores followed mary Choisy ) gave by his monograph in De Candolles Prodromus is of great interest little here. Choisy mentions 60 species, six of which are but known. The and work the most important extensive on genus is Meissner’s 2 ) in the Flora Brasiliensis. Meissner gives a general view of the Brazilian species, but also adds a few others, but not Brazilian. The total number he mentions several them. A number amounts to 62, new ones being among of new species have still been described after Meissner, from South justly or unjustly as new, the greater part America, but also from Mexico and the West Indian Islands. However revision of the did the after a general genus not see light Chois y's Monograph. 2. MORPHOLOGY. Roots. Roots annual the former or mostly perennial, in case thin, vertical with slender lateral branches, in the latter thin or mostly thicker and then often a perpendicular tap-root, also oblique or almost horizontal. Towards the top the root generally becomes gradually thicker and lignescent and bears at the crown one or mostly more stems. In E. pusillus Choisy adventitious roots often occur at the nodes, in E. nummularius L., this is usual. Stems. In the frutescent and suffrutescent species the stems are mostly erect, are either branched or not, the branches the often erecto-patent; height is generally but small, the largest 1.20 the forms attain a height of about metre. In perennial species the stem or the stems are erect or ascending or also they are often often prostrate, branched in more or less degree, lignescent at the base; in the few annual species the stems are mostly upright: this is often the case in annual specimens of perennial species, at least, in so far as they are known. Geneve VIII Conv. Rar. *) Choisy in Mem. Soc. Phys. (1837) p. 69; id. id. Prodr. 441. (1838) p. 147: in DC. IX (1845) p. 2 Mart. VII ) Meissner in FI. Bras. (1869) p. 329. 6 Leaves. The leaves small are to fairly large: very large leaves do not occur. Species with large leaves are for example E. and E. also E. and E. cardiophyllus latifolius ; in glaber num- mulariusrather leaves when large may occur, growing in a fertile habitat. small almost scale-like E. They are very to in The with squamosus. leaves are always alternate, entire margin, their form from subulate varies to linear, lanceolate, oblong, ovate and orbicular with intermediate every transition. They are sess- ile or short-petiolate; long petioles do not occur. In general the leaves are membranaceous, in some cases they are somewhat thicker. The indumentum variable: the kind of is very pubescence most prevailing consists of appressed, loosely oppressed or spreading to patent villose hairs, often long and mostly soft. Sericeous hairs also occur very frequently: these are always strongly appressed, generally more or less shining, straight, all pointing in the same direction. Now and then a woolly indumen- tum is found, also a short tomentum, the latter often mixed with hairs. All kinds of the longer transitions appear in pubescence and also the of the hairs variable. density is very The nervation consists of midrib a and one to several pairs of lateral nerves. Often the nervation becomes indistinct owing to the dense hairiness. Generally it is most distinctly to be seen underneath. The lateral nerves arise at different heights in the leaf or they arise quite near the base. This is especially the case in leaves with a broad subcordate or cordate leaf-base. I But also it occurs in narrower leaves. Here refer to E. sericeus Sw. in which 1 or more pairs of lateral nerves always arise at the base and are long-ascending.