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

1106 PONTEDERIACEAE
(2003) also mapped several counties in the Gulf Prairies and Marshes; no county distribution
map is provided; se Canada (Ont.) and widely scattered in the U.S. Native of Japan. [Z. matrella var.
japonica (Steud.) Sasaki] This species is used for lawns and playing fields (Watson & Dallwitz
1992). According to Anderson (2003), this was “the first species of Zoysia introduced into cultivation
in the United States, with the introduction of the cultivar ‘Meyer’ in the 1950s. It is the most
cold-tolerant and coarsely textured of the three species … and is the only species that is currently
available as seed in the United States. The other two species treated here can be established from
seed, but there are currently no commercial sources of either one in the United States.” I
Zoysia matrella (L.) Merr., (Derivation unknown, but possibly from an Urdu word mehtar, headman,
because the original author gives the location of the type as from Malabar, India), MANILA
TEMPLE GRASS, MANILA GRASS. Leaf blades to 7 cm long, weakly to strongly involute; inflorescence
1–4 cm long; spikelets 2.1–3.2 mm long, unawned or with awn to 1 mm long. Persisting or
possibly escaping from lawns; included based on indication by S. Anderson (pers. comm.) that
it possibly occurs in the area; no specimens have been seen and we are not aware of a county
record; no county distribution map is provided; FL, NM, and possibly TX. Native of the coasts of
the Indian Ocean. [Agrostis matrella L., Z. pungens Willd.] This species is considered by some authorities
to be a significant weed species (Watson & Dallwitz 1992). According to Anderson
(2003), “Many of the Zoysia lawn grasses grown in the southern and eastern United States are
derived from hybrids between Z. matrella and Z. pacifica or Z. japonica, and have retained
many of the characteristics of Z. matrella.” I
Zoysia pacifica (Goudswaard) M. Hotta & Kuroki, (of the Pacific), MASCARENE GRASS,
MASCARENE TEMPLE GRASS, KOREAN VELVET GRASS. Leaf blades 3 cm or less long, involute to
strongly convolute (the margins overlapping); inflorescence 0.4–2 cm long; spikelets 2.2–2.9
mm long, 0.5–0.8 mm wide, lanceolate to linear, unawned or with awn to 0.5 mm. Persisting or
possibly escaping from lawns; included for East TX based on indication by S. Anderson (pers.
comm.) that it possibly occurs in the area; no specimens have been seen and we are not aware of
a county record; no county distribution map is provided; CA, FL, and possibly TX. Native of
coasts of the w Pacific Ocean. [Z. matrella var. pacifica Goudswaard, Z. tenuifolia of authors not
Willd. ex Thiele] This is the least cold-tolerant of the three species included here and is not a
common lawn grass in the U.S. (Anderson 2003). “The cultivar ‘Cashmere’ has many of the
characteristics of Z. pacifica; it is probably derived from a hybrid between Z. matrella and Z.
pacifica (Anderson 2003).” I
PONTEDERIACEAE Kunth
WATER-HYACINTH OR PICKEREL-WEED FAMILY
Glabrous perennial or annual herbs; leaves basal or alternate, simple, entire, both sessile and
petiolate leaves often present; flowers solitary or in spikes, the inflorescence subtended by a
spathe-like bract; perianth parts united proximally to form a very slender basal tube; perianth
lobes 6, one differing slightly or greatly in size, shape, or coloration; stamens 3 or 6; pistil 1;
ovary superior; fruit a many-seeded capsule or a 1-seeded utricle.
AA small (ca. 30 species in 6 genera—Horn 2002) family of freshwater aquatic herbs of tropical
and warm areas nearly worldwide, but especially in the Americas, with a few in the n temperate
zone. Some are problematic weeds; a number are cultivated as ornamentals. The family
appears related to such familes as the Hamemodoraceae and Commelinaceae (Chase et al.
2000; Reveal & Pires 2002). (subclass Liliidae—Cronquist; order Commelinales—APG II)
FAMILY RECOGNITION IN THE FIELD: rooted or free-floating, wet area or aquatic herbs; flowers
often conspicuous, the perianth petaloid; inflorescence a solitary flower or a spike, subtended
by a spathe-like bract.