الفهرس 
Section B: Literature reviewOnly 14 pages are availabe for public view
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Abstract
In the present study, 20 wild and ornamental species representing four subfamilies out of five belonging to Apocynaceae s. l. to (APG, 2003, 2009 & 2016). The studied species were collected from different localities and botanical gardens from Egypt and Libya. The wild species were identified according to Täckholm (1974) & Boulos (2000) while the ornamental species by the aid of Bailey (1949).
The morphological characters including viz. whole plant, lamina vein architecture, lamina epidermal characters and pollen grains characters using LM & SEM were investigated and numerically analyzed to detect the phonetic relationship between the studied species and barcoding DNA sequencing (rbcL) was cldistically analyzed to detect the phylogenetic relationship between the studied species.
The obtained results might be summarized in the following point:
1. The stem was generally erect in most of the studied species or weak in Cynanchum acutum and Huernia andreaeana.
2. Leaves rudimentary in Huernia andreaeana or simple foilage with entire margin in the rest of the studied species.
3. The significant variation in flower structure mainly androecium and gynoecium considered as of valuable taxonomic criteria in differentiation between the studied taxa:
• Inflorescence type racemose as in Cerbera odollam, Gomphocarpus sinaicus and Solenostemma argel or cymose in 17 studied species and corolla tube shape rotate as in Cryptostegia grandiflora, Campanulate as in the studied species of (Asclepiadoideae), funnel or salver as in the studied species of (Apocynoideae and Rauvolfioideae).
• The anthers adhered to stigma only as in Cryptostegia grandiflora, adhered to styles and stigmas as in the studied species of Asclepiadoideae (gynostegium) or not adhered to style nor stigma as in the studied species of (Apocynoideae and Rauvolfioideae) and that help in the identification of the studied species.
• Carpels united throughout as in the studied species of (Apocynoideae and Rauvolfioideae) or free below and united above as in the studied species of (Asclepiadoideae and Periplocoideae).
• Stigma forming globose head or pentagonal head as in the studied species of (Asclepiadoideae and Periplocoideae) or cylindrical, armed or bilobed as in studied species of (Apocynoideae and Rauvolfioideae).
4. The leaves are amphistomatic as in Catharanthus roseus, Gomphocarpus sinaicus, Calotropis procera and Solenostemma argel or hypostomatic as in the rest 15 studied species. The leaves heterostomatic as in Cascabela thevetia and Plumeria obtusa or homostomatic as in the rest 17 studied species.
5. Trichomes glandular (clavate) as in Gomphocarpus sinaicus or eglandular unicellular as in Adenium obesum, Catharanthus roseus, Nerium oleander, eglandular multicellular as in Solenostemma argel or wanting trichomes as in the rest studied species.
6. Pollen association monads as in the studied species of (Apocynoideae and Rauvolfioideae), pseudo-pollinia as in Cryptostegia grandiflora (Periplocoideae) and is considered a transition link between the studied species of Rauvolfioideae, Apocynoideae and Asclepiadoideae and true pollinia as in the studied species of (Asclepiadoideae).
7. In Carissa carandas, the pollen class is colpate and colporate (new observation and record). In Carissa macrocarpa (Rauvolfioideae), the porate pollen encourages the grouping of it with the studied species of Apocynoideae.
8. Monad pollen sculpture psilate, scarbate-foveate, foveolate or glebulate, pollinium surface sculpture tuberculate, reticulate, colliculate, reticulate-foveate or psilate. Aperturate pollen is from simple vs. composite.
9. Pendulous pollinium recorded in Asclepias curassavica, Calotropis procera, Gomphocarpus sinaicus, Huernia andreaeana and Solenostemma argel or erect pollinium as in Cynanchum acutum. Basal attachment of translator as in Asclepias curassavica, Calotropis procera, Cynanchum acutum, Gomphocarpus sinaicus and Solenostemma argel or apical attachment as in Huernia andreaeana.
10. Wing detected as in Huernia andreaeana or undetected in the studied species of (Asclepiadoideae).
11. The combined dendrogram based on (167 macromorphological characters states and 68 palynological characters states) clearly showed that, the studied species (Apocynaceae s.l.) separated in two series, four subseries, four clusters and four groups. This finding is in agreement with Bessey (1915), Benson (1957), Hutchinson (1963), Melchior (1964) and Takhtajan (1980) who support the splitting of Apocynaceae s. l. into two distinct taxonomic entities (Apocynaceae and Asclepiadaceae).
12. The obtained cladogram based on molecular data of cpDNA sequence of rbcL gene showed that the studied species (Apocynaceae s.l.) divided into four lineages at different bootstrap values. The studied species of Asclepiadoideae in one lineage and the remaining studied species (Periplocoideae, Apocynoideae and Rauvolfioideae) into three lineages. It was
support the treatment of Apocynaceae and Asclepiadaceae as one family (Apocynaceae s.l.).
The most effective dendrogram is that of the combined analysis of classical taxonomy (macromorphology & palynology) which splitting the studied species of Apocynaceae s.l. into two distinct taxonomic entities. This result is in agreement with Engler and Prantl’s (1897), Bessey (1915), Benson (1957), Hutchinson (1963), Melchior (1964), Bentham & Hooker (1862-1883), Takhtajan (1980) and Cronquist (1988).
On the other hand, The cladogram based on molecular data splitting the studied species of Apocynaceae s.l. into four lineages. This is in accord with Thorne 1992, Sennblad and Bremer (2002), Endress et al. (2007), Endress et al. (2014) and APG (2003, 2009 & 2016).
In the present study, owing to the relatively limited sample of genera & species. Recognition of familial and subfamilial classification of Apocynaceae s.l. was mainly based on significant variation in pollen morphology viz. pollinia apparatus vs. monad and wide range of morphological variation and we recommended for more accurate classification further studies and number of genera are needed.