keys to the vascular plants of east texas - Botanical Research ...

1104 POACEAE/ZOYSIA
monoecious perennial 1.5–3(–4) m tall, forming beds in wet ground or shallow water; ligule a
prominent membrane 6–20 mm long; leaf blades to 1.2 m long, 10–35 mm wide, flat, with
coarsely scabrous, cutting margins; panicle 30–60(–80) cm long, loose, the branches ascendingspreading,
with staminate spikelets toward base of branches and pistillate spikelets toward tips
of same branches; pedicels 1–7(–12) mm long; spikelets 1-flowered, 4–10 mm long, without
glumes, disarticulating at base of lemma; lemma and palea similar to each other (resembling 2
glumes), strongly ribbed; lemma of staminate floret acuminate or with awn 2 mm or less long;
stamens 6; lemma of pistillate floret short-awned (awn 2–4(–9) mm long); caryopsis modified
(pericarp mostly free from seed coat—Brandenburg 2003). Marshes, creek bottoms, and
lakeshores; widespread in e 1/2 of TX with a few locations further w; se U.S. from MD s to FL w
to MO, OK, and TX. May–Sep. [Zizania miliacea Michx.] This species is unusual in that after
shedding its seeds, the fertile culm elongates and axillary buds grow and produce leaves and
adventitious roots. If the now modified fertile culm topples over, the “buds” can contact the substrate
and take root, thus allowing more rapid exploitation of the habitat via asexual reproduction
(Holmes & Stalling 1990). Brandenburg (2003) suggested that the “air space between the
free pericarp and the seed” allows for bouyancy (i.e., the modified caryopsis floats) and thus dispersal
in this aquatic species.
ZOYSIA Willd. ZOYSIA, TEMPLE GRASS
Rhizomatous, mat-forming perennials to only 40 cm tall; ligule of hairs, 0.3 mm or less long,
leaf sheaths and blades � glabrous; inflorescence a terminal, solitary, spike-like raceme; spikelets
solitary, on short pedicels, with 1 floret, unawned or with awn to only 1.1 mm long; disarticulation
below the glume(s) or not occurring; lower glume usually absent; upper glume enclosing
spikelet; lemma thin; palea usually not present.
AA C4 genus of 11 species (Anderson 2003) ranging from se Asia to New Zealand, typically in
sandy coastal areas; a number are used as lawn grasses or for playing fields, particularly in open
xeric sites (Anderson 2002, 2003). The species occurring in East TX are generally salt tolerant
(Anderson 2002). Preliminary molecular analyses (Hilu & Alice 2001) suggest a possible relationship
between Zoysia, Spartina, and some species of both Eragrostis and Sporobolus. According to
Anderson (2003), a number of cultivars have been derived from Zoysia species, sometimes involving
hybridization. Further, “cultivars often exceed the normal range of variation for a species in
one or more respects,” and “hybridization has resulted in cultivars with vegetative characteristics
more like those of one species and reproductive characteristics more like those of another species.”
This treatment is derived primarily from Anderson (2003). (Named for Karl von Zois, 1756–
1800, plant collector of Carniola, Austria) (subfamily Chloridoideae, tribe Cynodonteae)
REFERENCES: Goudswaard 1980; Anderson 2002, 2003.
1. Leaf blades involute to convolute, to only 0.5 mm in diam.; raceme with 3–12 spikelets; peduncle
included or extending to 1 cm beyond the sheath of the subtending leaf _____________________ Z. pacifica
1. Leaf blades flat to involute, 0.5–5 mm wide; raceme with 10–50 spikelets; peduncle extending
(0.3–)1–6.5 cm beyond the sheath of the subtending leaf.
2. Pedicels 1.6–3.5 mm long; spikelets ovate, 1–1.4 mm wide; culm internodes 2–10 mm long;
leaf blades ascending ___________________________________________________________ Z. japonica
2. Pedicels 0.6–1.6 mm long; spikelets lanceolate, 0.6–1 mm wide; culm internodes 5–40 mm
long, all plants with at least some internodes more than 14 mm long; leaf blades spreading
_____________________________________________________________________________ Z. matrella
Zoysia japonica Steud., (of Japan), JAPANESE LAWN GRASS, KOREA TEMPLE GRASS. Leaf blades to 6.5
cm long, flat to involute; inflorescence 2.5–4.5 cm long; spikelets 2.5–3.4 mm long, awned, the
awn to 1.1 mm long. Persisting or possibly escaping from lawns; Harris Co. (Anderson 2003)
near s margin of East TX; we, however, have seen no TX specimens of this species; Anderson