Systematic Revision of the Genus Pancratium L . ( Amaryllidaceae ) in Egypt with a New Addition

In Egypt, taxonomic aspects of the genus Pancratium L. (Amaryllidaceae, Pancratieae) were thoroughly studied to point out the most reliable characters for taxon delimitation. Here, we base our species on both geographical and morphological features. The detailed taxonomic revision of genus Pancratium is based on field studies and the examination of representative specimens together with the authentic types deposited in the major herbaria of Egypt and Kew. Variations in the aerial scape, spathe, perianth, corona-teeth, pistil, stamens, capsules and seeds, as well as those of leaf base and leaf orientation are good markers to separate the different species. As a result, five species are recognized, including P. trianthum as a new record to the flora of Egypt. It is restricted to the south-eastern corner of Egypt (Gebel Elba region) and being unique in possessing solitary spathe and long attenuate leaf base. A specific key and descriptions are given with typifications.


Introduction
Amaryllidaceae is well-marked by its showy lily-like epigynous flowers as in common onion.According to Meerow and Snijman (1998), Amaryllidaceae is about 800 species in 59 genera.Its center of diversity is in South America (28 genera) and Africa (19 genera).Eight genera are growing in Mediterranean and temperate regions of Asia, while only Crinum L., is represented in both the Old and New Worlds.It forms one of the climax groups in order Asparagales (Dahlgren et al., 1985;Fay and Chase, 1996).They are probably more closely related to the Alliaceae (formerly Liliaceae) and Hyacinthaceae but not to Hypoxidaceae, Agavaceae, Haemodoraceae or Alstroemeriaceae, with which they have formerly been united.It is separated from Liliaceae by its inferior ovary, in addition to its umbellate inflorescence with the characteristic bracts (spathe); the only character formerly separating the two families (Hutchinson, 1959).Species belonged to this family are mostly bulbous rarely rhizomatous herbaceous perennials of diverse habitats.
Many species represented as endangered species like Pancratium maritimum in its original range, the sandy coasts of the Mediterranean displaying the Sea (Grassi et al., 2005).Other species like Pancratium sickenbergeri is subjected to high levels of grazing.It is commonly found on sand dunes of the Negev Desert (Israel), and characterized by three phenological stages consisting, respectively, of inflorescence, leaves and no above-ground biomass: all stages are subject to herbivory by dorcas gazelles (Ward and Saltz, 1994;Saltz and Ward, 2000).When there is no aboveground biomass, the gazelles dig for underground parts of P. sickenbergeri and may consume all or part of the bulb, which contains most of the plant's volume (Ward and Saltz, 1994).
Within the framework of Engler and Prantl Pax (1887) and Pax and Hoffmann (1930) gave a comprehensive revision of the family Amaryllidaceae.According to the habit of the plant and the type of the inflorescence, they reclassified the Amaryllidaceae into 4 subfamilies: Amaryllidoideae, Agavoideae, Hypoxidoideae and Campanematoideae.Furthermore, they used the presence or absence of corona to subdivide Amaryllidoideae into 2 tribes: Amaryllideae and Narcisseae.Moreover, the former is divided into 6 subtribes; while the latter into 5 tribes.They included the genus Pancratium within the subtribe Eucharidinae of the tribe Narcissae.Hutchinson's classification (Hutchinson, 1934, 1959) was the first crucial recircumscription of Amaryllidaceae, defining the unifying character of the family to be an umbellate inflorescence subtended by an involucre of one or more spatheceous bracts.He used both vegetative and floral characters to classify the family into 13 tribes and included Pancratium within the tribe Eucharideae.Now, the present generic circumscription of the genus Pancratium within the tribe Pancratieae of Amaryllidaceae s. str., has gained wide acceptance (Dahlgren et al., 1985;Meerow, 1995;Meerow and Snijman, 1998;Müller-Doblis and Müller-Doblis, 1996;Traub, 1963).This is due to the presence of conspicuous false corona formed by the basal connation of the staminal filaments.

Synonyms
Zouchia Raf., Fl. Tellur. 4: 22 (1838 In Egypt, Amaryllidaceae is represented by two genera Pancratium and Narcissus, the latter is more widespread and common than the former.Therefore, this study focuses on the genus Pancratium as little attention has been paid to its taxonomy.Forsskal (1775) and Delile (1813Delile ( -1814) ) reported the occurrence of one species, whereas Boissier (1882) added two other species, of which P. tortifolium has been newly described.Sickenberger (1901) Boulos (2005), ), El Hadidi andFayed (1994/1995), Täckholm (1974) and Täckholm and Drar (1954).Pancratium aegyptiacum is conspecific to P. arabicum on the basis of the floral characters (especially the perianth).This study included several characters that are not used by Boulos (2005) in d delimiting its species.Moreover, synonyms are improved and some others are also included.Our proposed key is not dependent on Boulos's work (2005), as it included more morphological diagnostic characters.The aim of this study is to fill the gap in our knowledge of the taxonomy of the genus Pancratium in Egypt, by providing a critical revision of its species, clarifying some older and neglected ones, studying in more detail the most reliable taxonomic characters for the identification of taxa, with similar habitats.This revision revealed the presence of five species, of which P. trianthum Herb. is a new addition to the Flora of Egypt.
Herbarium study is based on the examination over 500 herbarium specimens kept in the different Egyptian major herbaria as well as the authentic specimens related to the studied Pancratium species.These herbaria were annotated during this study as Cairo University (CAI), the Agricultural Museum (CAIM), the National Research Centre (CAIRC) and the Royal Botanic Gardens in England (K ) (acronyms follow Holmgren et al., 1998).
Although Täckholm and Drar (1954, p. 359) cited P. aegyptiacum as a synonym to P. maritimum, they again cited Sickenberger specimens (recorded from El Arish; "Tell el Sheikh" and identified as P. aegyptiacum) as well as those of Schweinfurth (recorded from Cairo; Birket el Sab' and Damietta and identified as P. aegyptiacum) with query as P. arabicum (1954, p. 361).However, the diagnostic characters of P. aegyptiacum emended by Sickenberger are: broad leaves, long perianth-tube (10-12 cm), long pedicel at anthesis (1.0-1.5 cm) and oblong-ovoid capsule valves are scattered throughout the range of variation in P. arabicum without strong geographical bias.

Fig. 7 .
Fig. 7. Distribution map of Pancratium sickenbergeri; specimens seen by the author; literature record for P. maritimum