Paspalum distichum subsp. paucispicatum (Vasey) Verloove & Reynders, 2021

Raab-Straube, Eckhard von & Raus, Thomas, 2023, Euro + Med-Checklist Notulae, 16, Willdenowia 53 (1), pp. 57-77 : 60-61

Paspalum distichum subsp. paucispicatum (Vasey) Verloove & Reynders

(≡ Paspalum paucispicatum Vasey ) – Fig. 3.

N Bu: Bulgaria: Danubian plain, Pleven province, Belene municipality, Hisarlaka locality, about 4 km NW of Belene, 43°40'53.4''N, 25°05'51.43''E, 20 m, seasonally wet depression at shoreline of Danube river, population covering c. 20 m ², with flowering individuals, associated with Amorpha fruticosa L., Bolboschoenus maritimus (L.) Palla (aggregate), Cyperus glomeratus L., Erigeron annuus (L.) Desf. and Xanthium orientale subsp. italicum (Moretti) Greuter , 20 Aug 2022, Kunev (SO 108191; SOM 177790, SOM 177791); ibid., Limana locality, about 6 km NW of Belene, 43°41'07.6''N, 25°03'55.9''E, 22 m, on muddy shores of an artificial lake connected to Danube river, vast population with flowering and almost fruiting individuals forming dense, uniform, 1–15-mwide stands around lake, 3 Oct 2022, Kunev (SO 108192, SOM 177792, SOM 177793).

– The taxon is new to Bulgaria, not mentioned or keyed out in Stoyanov & al. (2021). It was originally published as a species based on collections from Mexico but was subsequently reduced to a subspecies of Paspalum distichum L. ( Verloove & Reynders 2007). In Greece, P. distichum is a relatively recent introduction, with the first record from the Thessaloniki area in 1944 ( Oberdorfer 1954). It has spread rapidly and now occurs throughout Greece ( Dimopoulos & al. 2013, 2020). Paspalum distichum subsp. paucispicatum , as a naturalized alien in Europe, was previously known only from France ( Valdés & Scholz 2009 +). The Bulgarian plants completely match the French plants reported by Verloove & Reynders (2007). The populations are rather uniform, composed of robust plants with a somewhat glaucous appearance and considerable degree of pubescence on the leaf blades, sheaths and nodes. Most of the individuals were bearing 3-branched racemes. Normally, in P. distichum subsp. paucispicatum , spikes bear 2 rows of paired spikelets (appearing as 4 rows). On the other hand, the Bulgarian populations of P. distichum subsp. distichum are clearly distinguished by their slender habit, bright green aspect, loose indumentum or most often complete lack of trichomes. Examination of the Bulgarian material of the genus Paspalum L. kept in SO, SOA and SOM showed that only the typical P. distichum subsp. distichum has been collected in the country previously. Table 1 compares characters measured on specimens of both subspecies from Bulgaria to provide additional data to help distinguish the two taxa.

G. Kunev

Figures

Fig. 3. Paspalum distichum subsp. paucispicatum – A: general habit of typical plants; B: inflorescence, often 3-branched, rachis usually bearing 2 rows of paired spikelets (vs spikelets mostly not paired in P. distichum subsp. distichum); C: leaves and sheaths; D: node, usually bearing dense, long, bulbous-based trichomes. – Source of material: Bulgaria, Pleven Province, near Belene, 3 Oct 2022, Kunev (SO 108192, SOM 177792, SOM 177793). – Photographs by G. Kunev.