Literature review: Impact of Chilean needle grass ... - Weeds Australia

Figure 2. Anatomy of the seed of N. neesiana.
Panicle seed: (aerially exserted) consisting of cayopsis, enclosed by the palea and the lemma, the callus (woody pointed
extension of the lemma) and the awn; weight c. 6 mg (Gardener et al. 1999; this is the fresh green seed). Lemma hardened
(Bourdôt and Ryde 1986), conspicuously tuberculate (Verloove 2005), tubercular-scabrous (Jacobs et al. 1989), papillose
(Barkworth and Torres 2001, Zanin 2008), coriaceous (Martín Osorio et al. 2000), or rugose-papillose, especially near the apex
(Burkart 1969), or finely rugose-papillose, particularly near the crown (Barkworth 2006), or papillose-scabrid (Walsh 1994), with 5
(Hayward and Druce 1919, Jacobs et al. 1989) conspicuous (Walsh 1994) or inconspicuous (Martín Osorio et al. 2000) nerves;
lemma 6-10 (mostly 8-10) mm long excluding the corona (Walsh 1994), 8-14.5 mm long including callus (Martín Osorio et al.
2000), about 8 mm long including callus (Burbidge and Gray 1970), c. 10 mm (Weber 2003), or 7-10-(13) mm (Moraldo 1986), 5.9-
10 mm (Zanin 2008), or to 6 mm long (Jacobs et al. 1989); constricted below the crown (Barkworth 2006); glabrous except for the
lower half on the veins (Verloove 2005), midveins pilose proximally, glabrous between the veins at maturity (Barkworth 2006),
median nerve with long hairs (Jacobs et al. 1989), glabrous except near the callus and midrib (Walsh 1994), lobes minute (Jacobs
et al. 1989); often purple (Barkworth 2006), pale brown at maturity (Walsh 1994).
Corona (called a “crown” by Tsvelev 1977, Barkworth 1990 2006 and Barkworth and Torres 2001; a “membranous cupule” by Stace
1997 and a “crowned collar” by Walsh 1998), a fusion of the edges of the lemma at its apex resulting in a solid cylinder (Barkworth
1990), or “a concave platform with the [awn] joint inside” (Tsvelev 1977 p. 8), best developed on mature seed, although apparent on
immature (Muyt 2001), a prominent ridge (Jacobs et al. 1989), usually wider than long, sides usually flaring somewhat distally
(Barkworth 2006), 0.8-1.3 x 0.7-1.1 mm (Zanin 2008), c. 1 mm wide and high (Verloove 2005), 0.6-1.6 mm high (Burkart 1969), 1.5
mm (Baeza et al. 2007), c. 0.7 mm (Moraldo 1986), 0.4-1.6 mm (Barkworth 2006), 0.5-1 mm (Barkworth and Torres 2001), or up to
1 mm (Jacobs et al. 1989) long, c. 1 mm long excluding the apical spines (Walsh 1994), cupuliform, “bone-like”, constricted
(Verloove 2005) and narrower (Martín Osorio et al. 2000) at the base, glabrous (Jacobs et al. 1989), with, at the apex, a
conspicuous ring of cilia (Burbidge and Gray 1970) or denticulate hairs with a clearly broadened base (i.e. “conspicuously triangular”
(Verloove 2005 p. 107)), or spreading spines 0.2-0.5 (Walsh 1994, 1998), to 0.5 m (Barkworth 2006),0.6-1.6 mm (Martín Osorio et
al. 2000) or to 1 mm (Jacobs et al. 1989, Edgar and Connor 2000) long, the spines elongating as the seed matures (Walsh 1998).
Violet or violet-suffused (Jacobs et al. 1989) or dark violet (Martín Osorio et al. 2000). The corona functions to ensure no
backward movement of the seed once it has lodged in fur or penetrated soil or litter, even after the awn becomes detached (Slay
2002a).
Palea oval, much shorter than lemma (Jacobs et al. 1989), up to one third of the lemma in length (Martín Osorio et al. 2000), 1.5-
2 x 0.5-0.7 mm (Baeza et al. 2007), 1.2-1.4 mm (Burkart 1969), 1.5 mm (Jacobs et al. 1989), 1-2 mm (Walsh 1994, Zanin 2008),
1-2.5 mm long, membranous (Verloove 2005, Baeza et al. 2007), transparent (Baeza et al. 2007), hyaline (Walsh 1994, Martín
Osorio et al. 2000, Baeza et al. 2007, Zanin 2008), glabrous (Walsh 1994, Martín Osorio et al. 2000,Verloove 2005, Baeza et al.
2007), nerveless (Jacobs et al. 1989) but “internerve” glabrous (Jacobs et al. 1989); apex 2-denticulate (Baeza et al. 2007).
Awn persistent (Edgar et al. 1991); “extremely strong” (Slay 2002c); robust, 60-90 mm (Moraldo 1986, Walsh 1994 1998,
McLaren, Stajsic and Iaconis. 2004), 50-90 mm (Weber 2003, Jessop et al. 2006), 60-70 mm (Burbidge and Gray 1970), to 70
mm (Jacobs et al. 1989), 60-80 mm (Bourdôt and Ryde 1986), 60-90 mm (Zanin 2008), up to 70 mm Slay (2002c), 6-9.5 cm
(Barkworth and Torres 2001, Verloove 2005), 5-12 cm (Burkart 1969, Barkworth 2006), 6-12 cm (Martín Osorio et al. 2000), 44-
70 mm long (Baeza et al. 2007) [total range of awn lengths cited = 44-120 mm]; bent above the middle (Hayward and Druce
1919), 15-30 mm to the first bend (Walsh 1994), hygroscopic (Murbach 1900, Bourdôt and Ryde 1986), with 1 (Bourdôt and
Ryde 1986, Jacobs et al. 1989, Edgar and Connor 2000), 1 or 2 (Slay 2002c), 2 (Burbidge and Gray 1970, Walsh 1994, Barkworth
and Torres 2001, Martín Osorio et al. 2000, Baeza et al. 2007), often 2 (Storrie and Lowien 2003), or 2-3 (Carolin and Tindale
1994) bends (“clearly twice-geniculate” Barkworth 2006); initially violet/green in colour, turning brown as seed matures (Slay
2002a); column stout (Weber 2003), tightly twisted (Jacobs et al. 1989, Edgar and Connor 2000), spirally twisted (Weber 2003),
appearing like a ‘corkscrew’ (Slay 2002c), long-hairy (Jacobs et al. 1989, Edgar and Connor 2000), pubescent (Baeza et al. 2007),
or sub-plumose (Burbidge and Gray 1970), or “corto-pilosa” at the base (Zanin 2008 p. 90); 25 mm long, an intermediate section
about 15 mm long that is shallowly twisted with short stiff hairs (Jacobs et al. 1989, Edgar and Connor 2000) and straight
(Barkworth and Torres 2001, Barkworth 2006), the lower section, about one third of the lower half of the awn spiralled and
covered with hairs (Martín Osorio et al. 2000); and a terminal section, the arista (bristle or seta), scabrid to 35 mm long (Jacobs
et al. 1989, Edgar and Connor 2000), “usually intertwined with awns of adjacent florets” (Jacobs et al. 1989).
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