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

478 BROMELIACEAE/TILLANDSIA
REFERENCES: Smith 1938; 1961; Smith & Wood 1975; Benzing 1976, 1994, 2000; Smith & Downs
1977; Benzing et al. 1978; Brown & Gilmartin 1984, 1989; Dahlgren et al. 1985; Gilmartin &
Brown 1987; Ranker et al. 1990; Martin 1994; Terry et al. 1997a, 1997b; Smith & Till 1998; Butcher
2000; Crayn et al. 2000; Horres et al. 2000; Luther & Brown 2000.
TILLANDSIA L. BALL-MOSS, AIRPLANT, NEEDLE-LEAF
Xerophytic epiphytes largely covered with multicellular peltate scales or trichomes that collect
water and nutrients, the plants gray when dry, gray-green when wet; leaves entire; flowers perfect;
stamens 6; ovary superior; fruit a septicidal capsule; seeds with a basal plumose appendage.
AA tropical American genus of ca. 550 species (Luther & Brown 2000) of epiphytes (less often
lithophytes and terrestrials), typically with leaves in a rosette; some are cultivated as ornamentals.
Because of their grayish color, seedlings are sometimes confused with lichens (E.
McWilliams, pers. comm.). Since the epiphytic habit often results in water stress, many epiphytic
bromeliads, including Tillandsia species, use their extremely specialized stellate or
scale-like, multicellular hairs to reflect sunlight, reduce water loss, and serve as the primary
organ for absorption of water and nutrients. The two East TX species can be described as “atmospheric
epiphytic” or “atmospheric” type epiphytes (Benzing et al. 1978; Crayn 2000) which
are adapted for water absorption from the air, in contrast to “tank” species which impound/
store water. In addition, ca. two-thirds of bromeliads, including both species of Tillandsia found
in East TX, exhibit CAM photosynthesis which allows night absorption and storage of CO2,
thereby reducing water loss through transpiration during the day (Benzing 1976, 2000; Martin
1994). Unlike parasitic plants such as Phoradendron (mistletoe in the Loranthaceae), epiphytes,
including those in the Bromeliaceae, do not harm trees; rather, they use them only for support.
(Named for Elias Tillands, 1640–1693, professor at Abo, Finland, who as a student crossing directly
from Stockholm, Sweden, was so seasick that he returned to Stockholm by walking more
than 1,000 miles around the head of the Gulf of Bothnia and hence assumed his surname (“by
land”); the genus was erroneously supposed by Linnaeus to dislike water)
REFERENCES: Birge 1911; McWilliams 1992, 1995; White et al. 1998a.
1. Plants typically in dense ball-like clumps; stems short, 10 cm or less long, completely concealed
by the overlapping leaf sheaths; flowers at the end of a scape, conspicuously exserted above the
leaves; petals violet or bluish _______________________________________________________ T. recurvata
1. Plants slender, wiry, usually curled, forming elongate hanging strands, not ball-like; stems elongate,
often several meters long, visible between the leaves; flowers apparently sessile among
the leaves; petals greenish or yellow-green ___________________________________________ T. usneoides
Tillandsia recurvata (L.) L., (recurved), BALL-MOSS, BUNCH-MOSS, SMALL BALL-MOSS, GALLITOS.
Plant rarely � 15 cm tall; roots present; leaves arising close together, recurving, elongate (2–17
cm long), very narrow (to ca. 3 mm wide), covered with scales; scape slender, with 1–2(–5) flowers;
petals violet or bluish; seeds comose with bristles in two series separated by several mm. In
East TX, usually epiphytic or further s and w also on rocks, tombstones, and utility wires; sw
margin of East TX (Bexar Co.) n and e to Harris, Hill, Henderson, Madison, and Walker cos.
(McWilliams 1992, 1995; White et al. 1998a) in the Blackland Prairie, Post Oak Savannah, and
Pineywoods; primarily s 1/2 of TX; apparently spreading e and ne (several populations are now
known from LA—E. McWilliams, pers. comm.); an introduced population on a single tree was
observed in Dallas (McWilliams 1992); AZ, FL, GA, LA, NM, and TX and s to Central and South
America. Flowering throughout the year. This species has expanded its geographic range in TX
over the past 80 years, perhaps in response to changing climate; such climate-sensitive species
may be able to serve as early indicators of projected regional climatic change (McWilliams
1995). White et al. (1998a), however, questioned this interpretation. m/303