Conventional keys for Convolvulaceae in the flora of Egypt

Rabei, S. & Abdel Khalik K. A.: Conventional keys for Convolvulaceae in the flora of Egypt. — Fl. Medit. 22: 45-62. 2012. — ISSN: 1120-4052 printed, 2240-4538 online. Three keys to 44 species belonging to the family Convolvulaceae in the flora of Egypt are prepared to facilitate the identification of those species, based on 72 characters. These keys were constructed using the DELTA key-generating programs. The first key was built using all characters and the second key was built using 56 characters (vegetative, floral and fruit characters). The first key is considered as main key and can be confirmed by the second key in the field. The third one was built using 16 characters (pollen grains, seed and cell wall characters) which are to be used to identify and confirm the specimen in the laboratory.


Introduction
Convolvulaceae (morning glory family) is a large family, comprising approximately 50-60 genera with some 1600-1700 species (Mabberley 1987), exhibiting a rich diversity of morphological characters and a wide range of ecological habitats.It is herbaceous, twining, or woody, climbing or trailing vines, shrubs or trees.Takhtajan (1997) placed this family in its own order, Convolvulales, due to a number of morphological characters.
Convolvulaceae has been studied by many authors.Hallier (1893) recognized the usefulness of pollen characters and divided the family into two subfamilies: Echinoconiae and Psiloconiae.Sengupta (1972) studied the pollen of 170 species in 30 genera, and described four pollen types, each with several subtypes.Tellera & Daners (2003) studied the pollen of 75 species, and described three main pollen types.Osman & Abdel Khalik (2005) studied the pollen morphology of Convolvulaceae in Egypt and recognized three main pollen types.Sampathkumar & Agyangar (1978) studied the seed coat anatomy and morphology of the family Convolvulaceae and separated Cuscuta into another family Cuscutaceae.Abdel Khalik & Osman (2007) investigated the seed morphology of 31 taxa of Convolvulaceae in Egypt and cited the importance of seed morphology to distinguish between the studied taxa.Abdel Khalik (2008) studied the phenetic characters of the Convolvulaceae in Egypt and recognized five main groups: Convolvuleae, Cuscuteae, Cresseae, Dichondreae and a mixed group from Ipomoeeae and Merremieae.
In the flora of Egypt, Convolvulaceae is represented by about 47 species belonging to 10 genera, assigned to 6 tribes (Boulos 2000).Members of these tribes are distributed over a wide range of habitats: weeds of farmland and waste places, desert herbs, subshrubs or shrubs in the Mediterranean coastal land, the oases, and the mountains of Sinai and Elba as well as inland salt marshes.
Members of the Convolvulaceae are easy to distinguish morphologically, but it is difficult to identify at species level.This is largely due to the wide range of morphological and structural modifications related to the plants' ability to adapt to a multitude of habitat types.Such plants possess similar floral and vegetative parts, which render their identification by manually constructed keys highly problematic.The problems extend further to the process of manual key construction for such taxa with unusual structural attributes so that the keys built for their identification depended almost invariably on floral and micromorphological characters.
DELTA (Descriptive Language for Taxonomy) has been selected to carry out the taxonomical work of this study.DELTA is a multipurpose format for generating identification keys (Dallwitz 1980;Dallwitz & Paine 1986;Partridge et al., 1988).It was designed as an easy and flexible format for recording descriptive data and for people to use it.On the other hand, a degree of complexity was necessary to avoid loss of significant information (Dallwitz 1993;Dallwitz & al. 2000).
Key-generating computer programs seemed to offer a useful tool to overcome the difficulties involved in botanical identification in general (El-Gazzar 1976).This view is supported by the many successes achieved in studies performed on various groups in different parts of the world (http://delta-intkey.com/www/refs.htm) and in Egypt (Rabei & El-Gazzar 2007;El-Gazzar & al. 2008;Rabei 2011).Therefore, we have embarked on the present study to benefit from the facilities of the flexible key-generating suite of programs DELTA (Dallwitz & al. 2000) in resolving the problems of identifying representatives of the Convolvulaceae in the flora of Egypt.

Material and Methods
The present work is based on the collections kept in Cairo University herbarium (CAI),Wageningen University Herbarium (WAG),as well as on fresh materials collected during field trips to the Mediterranean region, Eastern Desert, Isthmic Desert, Sinai, and the Nile Delta.The list of these species is shown in Appendix 1.The studied species are carefully examined for their general morphology.The available characters are recorded as well as some micromorphological characters (pollen and seed characters).DELTA program is used in this study for building keys.The development of the character list is an ongoing process aimed at eventually producing a list to record data for all the species of the Egyptian Convolvulaceae.Character order and wording are manipulated in the character list with the aim of improving the flow of language in the natural-language descriptions generated by CONFOR (Dallwitz & al. 1993;2000).Appendix 2 shows the characters (72) and character states scored for plant (vegetative, floral and fruit morphology), seed, and pollen morphology averaged for each taxa.Data for each species are coded in DELTA format.The coded description can be converted by the program CONFOR into the format used by KEY and Tonatr for producing automatic description (Watson & al. 1989;Dallwitz & al. 2000).CONFOR (Format-Conversion Program) is a program for translating DELTA-format data into other formats, including natural language.KEY (Key Generation Program) is a program for constructing taxonomic keys.Keys are produced in the conventional bracketed form or in tabular form in tree-diagram format.The KEY program (Dallwitz 1974) was used as a basis for pro ducing a traditional key to the species in the family.3 keys are generated using different characters combination.

CONFOR (Format Conversion
): CONFOR is used to manipulate the various types of data files used by the DELTA system.CONFOR translates input 'directives' and data files into output files in a variety of formats.Such formats include Natural Language descriptions.

Main Key
In this key all the characters are used except the size characters.This key can be used to identify the specimen in the field.using them in the field.However, in the third key size characters are used for confirmation in the laboratory.All the characters of pollen grains, seed and cell wall are used .
After any identification, it is good practice to check its accuracy by comparing the specimen with a description or illustrations of the taxon, or with other specimens in the herbarium known to belong to the taxon, and to use confirmatory keys.The excluded size characters were used with the other characters for generating Natural-language descriptions.
The main key and the second one are generating depending on vegetative, floral and fruit characters.These characters are available and easy to distinguish in the field or in the lab.However, Boulos (2000) used also pollen grains in his main key for identification of the genera of Convolvulaceae of Egypt.

Convolvulus arvensis L.
Plant life Not parasite.Plant colour Green.Perennial.Herb.Stem nature Herbaceous.Plant height 60 cm.Stem habit Prostrate to twining.Mode of perennation rhizomatous.Nature of branches Not spinescent.Plant surface Glabrous to sparsely hairs.Hairs patent Spreading.Hair shape Simple.Lower leaves arrangement No rosette.Green leaves Present.Leaves petiole Petiolate.Leaf petiole length 1.2 cm.Leaf venation Pinnate.Leaf shapes Sagittate to hastate.Leaf apex Obtuse to acute.Leaf margin Entire.Inflorescence Bracts present.Inflorescence position Axillary.Peduncle mean length 4 cm.Flowers numbers Solitary or in pairs.Flower pedicle Pedicellate.Flower bract Present.Sepal mean length 4.5 mm.Sepal shape Oblong to obovate.Sepal apex Apiculate.Sepal surface Glabrous.Sepals patent at fruit maturity Erect.Corolla shape Funnel-shape.Corolla margin Shallow lobed or bifid.Corolla mean length 20 mm.Corolla colour Pink to white.Corolla surface Glabrous with hairy bands outside.Filament mean length 8 mm.Filament surface With sessile glandular hairs at the base.Anther shape Oblong.Stamens and styles Included.Style number One.Style shape Filiform.Style surface Glabrous.Style length (compared to stigma) Longer than stigma.Styles branching Not forked.Stigma number 2. Stigma shape Cylindrical.Fruit mean length 6.5 mm.Fruit mean width 4.5 mm.Fruit dehiscence Dehiscent.Fruit shape Subglobose.Number of fruit locules 2. Fruit patent Recurved.Fruit surface Glabrous.Surface of fruit pedicel Hairy.Fruit pedicel mean length 14 mm.Pollen types Tricolpate.Pollen surface Smooth to micro-granulate.Pollen shape Prolate spheroidal.Exine sculpture Tectate, punctuate, micro-granulate.Number of seeds in fruit 4. Seed shape Pyramidal.Seed surface Glabrous.Seed architecture Tuberculate.Seed size( mm) (Length × width) 1.5-4 × 1.3-3.7.Seed colour Brown.Epidermal cell paterns Isodiametric, 4-5-6 polygonal or elongate in one direction.Anticlinal walls Straight.Relief of cell wall boundaries Raised.Sculpture of anticlinal boundaries Smooth.Curvature of outer periclinal cell wall Flat to concave.Secondary cell wall sculpture Micro-reticulate.