Paspalum racemosum Lamarck (1791: 176)

Faried, Ahmed M., 2018, A taxonomic synopsis of the genus Paspalum (Poaceae) in Egypt, including the first record of Paspalum vaginatum for the flora, Phytotaxa 336 (2), pp. 171-180 : 175-178

Paspalum racemosum Lamarck (1791: 176) .

Type:— PERU. San Martín, Rio Huallaga: 01 January 1790, C. D. Boutelou s.n. (holotype US- 2855976! (fragm. ex P), isotypes BAA00003827! (fragm. ex P), P00745920!).

= Paspalum stoloniferum Bosc (1794: 83) . Type:— PERU. San Martín, Rio Huallaga: Gouan s.n. (holotype US-80053!, isotype P00745921!).

Distribution:— Introduced in Egypt, where known from the Nile region.

Native to Southern America: Colombia; Ecuador and Peru ( Wilkin 2014). The species was first considered in Egypt by Boulos (2005); see Table 1. Paspalum racemosum was introduced to Egypt as a forage crop but apparently is no longer in cultivation (Boulos 2005). It is known in the country from only a single collection.

Representative specimen examined:— EGYPT. The Nile region: Giza, Gezira, Zohria garden, 5 May 1970, Ezz El Din s.n. (CAI).

Paspalum vaginatum Swartz (1788: 21) . Digitaria vaginata (Sw.) Magnier (1887: 120) . Panicum vaginatum (Sw.) Grenier & Godron (1856: 462) . Type:— JAMAICA. West Indies: O. P. Swartz s.n. (holotype S-R-4070!, isotype US-80042!).

Comments:— Paspalum vaginatum and P. distichum were recognized as distinct species ( Stapf 1899, Chase 1929, Chippendall 1955) until Launert (1970) recognized P. vaginatum as a synonym of P. distichum . Clayton (1972) and Renvoize & Clayton (1980) proposed rejection of the name P. distichum due to a mistake in its typification. This proposal was rejected (Nomenclature Committee for Vascular Plants Brummitt 1983). Loxton (1974) considered P. distichum to be a synonym of P. vaginatum . Paspalum distichum was again treated as a distinct species by Fosberg (1977) and Guédès (1981).

Paspalum vaginatum is a prostrate turf grass, perennial, with long rhizomes and stolons ( Fig. 2 , A). It is closely related to P. distichum , since both species are stoloniferous, have membranous ligules, have conjugate inflorescences and are members of the Disticha group ( Zuloaga & Morrone 2005). On the other hand, the species can be easily differentiated by several characters ( Table 2). According to Clayton & Renvoize (1986), the lack of a lower glume in the genus Paspalum is a useful taxonomic character. The lower glume is usually present in P. distichum as a small triangular scale or reduced to a small rim ( Fig. 3 : B, C), whereas in P. vaginatum the lower glume usually is absent ( Fig. 4 : B, C). Furthermore, the upper glume is minutely pubescent in Paspalum distichum ( Fig. 3 : D, E) and glabrous in P. vaginatum , as shown in Fig. 4 : D, E ( Loxton 1974, Gould 1975, Verloove & Reynders 2007).

Paspalum vaginatum is commonly known as seashore paspalum or simply paspalum ( Duncan 2003).

Distribution:— Paspalum vaginatum is here newly recorded for the Flora of Egypt. It was collected from the Mediterranean coastal strip as well as from Giza and Assiut governorates ( Fig. 1 ). It is native to North and South America ( Wilkin 2014). It also is introduced in the neighboring countries of Saudi Arabia and Yemen (Chaudhary & Akram 1987, Wilkin 2014).

Many sources ( Swaine et al. 1979, Costa et al. 1996, Cantero et al. 1998, Ghazanfar 1999, Bhattacharjee et al. 2007, Miller et al. 2010, Shaw 2012) report the occurrence of Paspalum vaginatum throughout the world in saline coastal wetlands, brackish marshes, salt marshes, along coastal drainage creeks and on wet beach sands. Faried & Amro (2016), on the contrary, reported the species from warm and dry, desert habitats. Cardona et al. (1997) reported that P. vaginatum occurs in climatic conditions ranging from warm temperature to tropical.

Representative specimens examined:— EGYPT. The Mediterranean coastal strip: Alexandria, 40 km west of Alexandria, Al Fairouz resort, in a garden, 30°58’58.5”N, 29°34’35.1”E, 5 September 2016, A. Fayed s.n. ( ASTU) ; The Nile region: Cairo: Al Maadi , 29°57’55.5”N, 31°16’12.7”E, 9 September 2016, A. Faried s.n. ( ASTU) ; Assiut, 27°10’45.54” N, 31°11’54.31”E, 4 June 2016, A. Faried and A. Amro s.n. ( ASTU) ( Fig. 1 ) .

Figures

FIGURE 1. Distribution map of Paspalum species in Egypt. P. vaginatum (Î), P. dilatatum (Δ), P. distichum (z), P. racemosum („).

FIGURE 2. Paspalum vaginatum. A. Habit; B. Dorsal upper glume; C. Ventral upper glume; D. Dorsal lower lemma; E. Ventral lower lemma; F. Dorsal upper lemma; G. Ventral upper lemma; H. Palea and floret. A–H drawn by the author from A. Faried s.n. (ASTU).

FIGURE 3. Paspalum distichum. A. Whole Inflorescence; B. Segment of inflorescence; C. Ventral view of spikelet (showing the lower glume); D. Dorsal view of spikelet (showing nerves of upper glume); E. Side view of spikelet (showing the surface of upper glumes); F. Rachis; G. Leaf sheath with ligule. Photographs (A–G) were taken from L. Boulos 20014 (ASTU).

FIGURE 4. Paspalum vaginatum. A. Whole Inflorescence; B. Segment of inflorescence; C. Ventral view of spikelet (showing the lower glume); D. Dorsal view of spikelet (showing nerves of upper glume); E. Side view of spikelet (showing the surface of upper glumes); F. Rachis; G. Leaf sheath with ligule. Photographs (A–G) were taken from A. Faried and A. Amro s.n. (ASTU).