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

990 POACEAE/ORYZA
Roem. & Schult.] This taxon has been treated quite differently by various authorities. Hitchcock
(1951) and Kartesz (1994) recognized it as a separate species (O. setarius). Davey and Clayton
(1978), however, studied the group worldwide and concluded that O. setarius should be included
in O. hirtellus. Subsequently, Scholz (1981) recognized 11 subspecies in O. hirtellus, including
subsp. setarius. This subspecies was not recognized as a separate entity by either Crins
(1991), Jones et al. (1997), or Diggs et al. (1999). Most recent authorities (e.g., Pohl & Davidse
1994a; Kartesz 1999; Peterson et al. 1999; Wipff 2003h), however, treat it at the subspecific level,
and while there seems to be some geographical and morphological overlap between taxa
(Wipff 2003h), in order to recognize the variation present, it seems most appropriate to follow
these authorities. All TX material of this species falls within subsp. setarius. Other subspecies
found in the U.S. have either longer inflorescence branches, pilose leaf sheaths, or longer spikelets
(Peterson et al. 1999). This species has viscid (= adhesive, sticky) awns (Sorensen 1986)
which “are undoubtedly very efficient agents in seed dispersal” (Chippindall 1946). I
ORYZA L. RICE
AA tropical and subtropical C3 genus of ca. 20–22 wild species and 2 cultivated species, O. sativa
(ASIAN RICE) and O. glaberrima Steud. (AFRICAN RICE) (Lu et al. 2000; Terrell & Barkworth
ined.); the approximate number of species occurring in different parts of the world are: 12 species
in se Asia and Australia, 6 in Africa, and 3 in the New World (Tucker 1988). Oryza is closely
related to Leersia, CUT GRASS (Ge et al. 2002), and there has been some confusion concerning
generic limits. However, Leersia lacks glumes, which are consistently present in Oryza. There
is disagreement over spikelet structure in Oryza—e.g., the two bracts beneath the fertile floret
are sometimes interpreted as glumes (e.g., Terrell & Barkworth ined., and as done here) or by
other workers as sterile lemmas. Oryza sativa, ASIAN RICE or RICE, is arguably the world’s most
important food plant—it is the staple food for 1/2 or more of the world’s population (Heiser 1990;
Lu et al. 2000). ASIAN RICE is possibly derived from O. rufipogon Griff., a wild Asian grass, probably
first through selection as a weed in flooded Colocasia (TARO—Araceae) fields (ca. 5,000 BC
in the Lower Yangtze of China, in Thailand, and n India) and then through artificial selection
(Mabberley 1997). Another wild Asian grass, O. nivara Sharma & Shastry, is closely related and
may also be involved in the origin of ASIAN RICE (Lu et al. 2000). There is “some evidence that
the two major Asian races, tropical Indica and cool-tolerant Japonica, were domesticated independently”
(Clayton & Renvoize 1986). � Several species are considered significant weeds
(Watson & Dallwitz 1992), and O. rufipogon, BROWN-BEARD RICE, is considered a noxious weed
in CA and FL and is listed as a U.S. federal noxious weed (Kartesz 1999; USDA Natural Resources
Conservation Service 2002). (Greek: oryza, rice, derived from Arabic: eruz, rice—Tucker
1988) (subfamily Ehrhartoideae, tribe Oryzeae)
REFERENCES: Tateoka 1963; Adair et al. 1973; Chang 1976, 1988; Terrell 1983; Terrell et al. 1983;
Duistermaat 1987; Tucker 1988; Duvall et al. 1993a; Chaturvedi et al. 1998; Whang et al. 1998; Lu
et al. 2000; Terrell & Barkworth ined.
Oryza sativa L., (cultivated, sown, or planted), RICE, ASIAN RICE, CULTIVATED RICE, RED RICE. Tufted
annual; culms erect, 50–160(–200) cm tall; leaf sheaths usually auriculate; ligule a 2-lobed
membrane, ca. 4–16 mm long, rarely longer; leaf blades 20–50(–70) cm long, 5–20 mm wide,
sometimes thickened and spongy basally near midrib; inflorescence a panicle, the branches
often drooping; spikelets laterally flattened, 7–11 mm long (excluding awns), 2–4 mm wide,
sometimes reddish, with 1 perfect flower subtended by 2 pointed, linear-lanceolate glumes usually
1.5–3 mm long; disarticulation below glumes; lemma oblong-ovate, keeled, varying from
glabrous to hirsute, usually short-pointed and awnless or with an awn to 5(–70) mm long; palea
similar to lemma, awnless; stamens 6. Moist areas; se part of East TX; also Gulf Prairies and
Marshes and n South TX Plains; se Canada (Ont.) and se U.S. from VA s to GA w to MO, OK, and
TX, also CA. Jul–Dec. Native of Asia. In the s part of East TX and in the Gulf Prairies and