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

SAGITTARIA/ALISMATACEAE
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long terete petioles and definite blades (lanceolate to broadly ovate); achenes 1.6–2.5
mm long _________________________________________________________________ S. lancifolia
1. Leaf blades usually sagittate, with conspicuous, projecting, basal lobes; filaments glabrous.
5. Sepals of pistillate flowers in fruit 5–14 mm long, appressed, enclosing the achenes; stalks
(pedicels) of fruiting “heads” usually recurved and noticeably thickened (usually ca. 1–2 mm
wide); petioles terete; most flowers perfect (the predominantly pistillate flowers have a ring
of sterile stamens) _________________________________________________________ S. montevidensis
5. Sepals of pistillate flowers in fruit 4–7 mm long, reflexed or spreading, not enclosing the
achenes; stalks (pedicels) of fruiting “heads” ascending or if recurved then not noticeably thickened
(� 1 mm wide); petioles angular; few or no flowers perfect (pistillate flowers without a
ring of sterile stamens).
6. Basal lobes of leaf blade significantly longer than (commonly twice as long as) blade body __ S. longiloba
6. Basal lobes of leaf blade usually � equal to or shorter than blade body.
7. Lower floral bracts triangular-ovate, obtuse or acute, 3–12 mm long, connate 1/4 or
more total length; achene beak projecting � horizontally or slightly downcurved, the
wing of the achene extending � smoothly to upper surface of the beak _______________ S. latifolia
7. Lower floral bracts lanceolate to narrowly triangular, acuminate, 12–30(–50) mm long,
distinct or connate � 1/4 total length; achene beak projecting upward at an angle, the
wing of the achene not extending smoothly to upper surface of the beak, with a definite
interruption (“saddle”-like) _____________________________________________ S. brevirostra
Sagittaria brevirostra Mack. & Bush, (short-beaked), SHORT-BEAK ARROWHEAD, MIDWESTERN AR-
ROWHEAD. Leaves to 0.6 m long; leaf blades to 25(–30) cm long and 11(–20) cm wide (usually
smaller), usually sagittate; bracts of inflorescence not papillose; sepals reflexed or spreading, not
enclosing mature achenes; petals 8–15 mm long; filaments cylindric, usually longer than anthers,
glabrous; achenes 2.1–3.1 mm long; achene beak inserted laterally, ascending apically, broadbased,
0.4–1.7 mm long. Rivers, ditches, other wet areas; Dallas, Ellis, Grayson (BRIT), and Collin
(Turner et al. 2003) cos. in Blackland Prairie and Polk Co. (Turner et al. 2003) in the Pineywoods;
also Rolling Plains; sc Canada (Sask.) and mostly c U.S. from MI s to AL and w to ND and NM,
also CA. Jun–Aug. [S. engelmanniana J.G. Smith subsp. brevirostra (Mack. & Bush) Bogin]
Sagittaria graminea Michx., (resembling grass), GRASS-LEAF ARROWHEAD, GRASSY ARROWHEAD.
Leaves phyllodial (= petiole and blade indistinct) or with blades; juvenile leaves and early season
leaves phyllodial, the later leaves often with blades; phyllodial leaves variable in length and
width, to ca. 2.5(–4) cm wide; leaf blades variable in shape, ranging from linear to linear-lanceolate
to elliptic; inflorescences racemose; bracts of inflorescence not papillose; sepals reflexed
or spreading, not enclosing fruiting aggregate; petals 6–15 mm long; filaments broadly dilated,
shorter than anthers, pubescent; achenes 1.5–2.8 mm long; achene beak laterally inserted just
below summit, ascending, subulate, to 0.3 mm long or obsolete. In mud or shallow water,
ditches, marshes, other wet areas; widespread in East TX; also Gulf Prairies and Marshes; se
Canada and widespread in e 1/2 of the U.S., also WA. Apr–Nov. [S. cycloptera (J.G. Sm.) C. Mohr, S.
lancifolia L. var. angustifolia (Lindl.) Griseb., S. stolonifera Engelm. & A. Gray]
Sagittaria lancifolia L. subsp. media (P. Micheli) Bogin, (sp.: lance-leaved; subsp.: intermediate, the
middle), SCYTHE-FRUIT ARROWHEAD, BULL-TONGUE ARROWHEAD. Leaf blades lanceolate to
broadly ovate, to 40 cm long and 10(–16) cm wide; petioles terete; bracts of inflorescence papillose
and sometimes also ridged, to 35 mm long, basally connate; sepals reflexed to spreading,
not enclosing fruiting aggregate, papillose; petals ca. 8–20 mm long; filaments cylindric, longer
than anthers, pubescent; beak of achene inserted laterally near apex of achene, ascending, to
0.8 mm long. Swamps, marshes, or other wet areas; s Pineywoods and s Post Oak Savannah, also
Hatch et al. (1990) indicated occurrence in the Blackland Prairie (however, we have seen no confirming
specimens from the Blackland Prairie); also Gulf Prairies and Marshes and South TX