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

696 IRIDACEAE/SISYRINCHIUM
SISYRINCHIUM L. BLUE-EYED-GRASS, GRASS-VIOLET
Perennials or less commonly annuals from fleshy-fibrous roots, sometimes with obscure rhizomes;
vegetatively like miniature irises, but often described as grass-like; stems typically 2winged,
unbranched and leaves all basal or stems branched and leaves basal and cauline; leaves
few, distichous (2-ranked), linear, flat; flowers few, in small cyme-like clusters, from a pair of
bracts (referred to as the spathe), closed at night or in cloudy weather, not fragrant; peduncles �
indistinguishable from stems; perianth radially symmetrical, the � separate tepals similar or
alternating narrow and wide, of various shades of blue to purple, violet, rose, white, or yellow,
the flowers usually with a yellow center or “eye,” or in one species (S. rosulatum) with a purple
to maroon “eye ring”; stamens with filaments usually connate into a narrow column, the anthers
separate.
AA mainly American (especially Central and South America) genus of ca. 80 species with 1 in
Hawaii, 1 in Ireland, and 1 in New Zealand (these possibly naturalized) (Cholewa & Henderson
2002); some are cultivated as ornamentals. A number of species have “oil flowers” which have
elaiophores (= oil-secreting organs). The oils (instead of nectar or pollen) produced by these
structures serve as a reward for specialized bees which pollinate the flowers (Buchmann 1987;
Cocucci & Vogel 2001). The genus is a variable, phenotypically plastic, and taxonomically difficult
group that needs detailed study; hybridization occurs (particularly in TX), further complicating
the picture (see note following S. sagittiferum). In addition, Cholewa and Henderson
(2002) pointed out that, “Sisyrinchium is a complex polyploid taxon in which the species are
not always easily distinguished.” Shinners (1958) indicated that this is “One of the most difficult
genera in the Texas flora.” Mosquin (1970) proposed combining a number of the species, including
S. albidum, S. angustifolium, S. campestre, and S. langloisii, into a single, widespread, variable
taxon. While there are many taxonomic problems to be worked out in this genus, recent
studies (e.g., Hornberger 1991; Cholewa & Henderson 2002) have somewhat clarified the situation.
In the following treatment, we are in general following the species concepts of Cholewa
and Henderson (2002). It should be noted that species are variable, intermediates are to be expected,
and fresh or carefully pressed material is sometimes necessary for definitive identification.
Unfortunately, “Accurate identification requires examining more than one individual in
order to discount uncommon or atypical character states” (Cholewa & Henderson 2002). Although
the flowers are relatively small, the plants are often extremely abundant, making showy
displays along roadsides and open areas. The most widely used common name, BLUE-EYED-
GRASS, is doubly incorrect, the plants having neither a blue center or “eye” nor being related to
grasses; they do, however, often look superficially like grasses with bluish flowers. (Name used
by Theophrastus for some plant, later transferred to this genus; possibly derived from Greek:
sys, pig, and rhynchus, snout or beak, in reference to pigs grubbing for the roots—Shosteck 1974)
REFERENCES: Bicknell 1901; Shinners 1962a; Oliver 1969; Mosquin 1970; Goldblatt et al. 1989,
1990; Hornberger 1991; Cocucci & Vogel 2001; Cholewa & Henderson 2002.
1. Perianth campanulate-urceolate, flaring distally rather than at base; tepals lavender-pink to lavender-rose,
purple-rose, yellow, or white; plants usually annuals (can be short-lived perennials).
2. Perianth with a yellow “eye,” the tepals otherwise lavender-pink to purple-rose, occasionally
white, rarely yellow; 3–6.3 mm long; capsules more elongate than globose, ca. 4–5.5 mm long;
stems with 3–5 nodes; filaments connate nearly their full length ___________________________ S. minus
2. Perianth with a purple to maroon or red-brown “eye ring” or markings near center (however,
innermost throat of perianth can be yellow), the tepals otherwise yellow to white, pink, or
lavender-rose, (4–)5–11(–16 mm) long; capsules globose, ca. 2–4 mm long; stems with only
1–2(–3) nodes; filaments connate 1/2 their length or less ______________________________ S. rosulatum
1. Perianth � rotate, flaring from base or even reflexed; tepals pale to deep blue to blue-purple,
blue-violet, or white; plants perennials.