SCB Tecate Cypress Poster

1
Phylogeny of the Acanthaceae, Acanthus Family
Lisa Markovchick-Nicholls Biology Department, San
Diego State University
Family Characterization

• Diversity Biogeography
• 229 genera and gt3000 species.
• Mostly pan-tropical, from the tropics to
  temperate regions (Simpson 2006, Stevens 2001).
  See Figure 1.
• Economic Importance
• Several cultivated ornamentals (Simpson 2006).
• Specific family members also reportedly have a
  wide range of medicinal uses, including
• As antioxidants (Chen et al. 206)
• To relieve drug addiction symptoms and increase
  neuron activity in brain regions responsible for
  reward and locomotor behavior (Thongsaard et al.
  2005).

• Habit Characteristics
• (Hickman 1993, Simpson 2006)
• Usually annual or perennial herbs or shrubs.
• Leaves generally simple and opposite.
• Inflorescence a bracted cyme, spike, or raceme
  of solitary flowers.
• Flowers bisexual, nearly radial to 2-lipped,
  calyx deeply 4-5 lobed, and corolla 4-5 lobed
  (Fig. 2).
• Stamens 2 or 4 and epipetalous. Anther sacs
  sometimes dissimilar in size or placement. See
  Figure 3 for example.
• Ovary superior with axile placentation (Fig. 2).
  
• Fruit explosively dehiscent loculicidal capsule.
• Nectaries often form disk at ovary base (Fig.5).

Figure 1. Biogeography from Heywood 1985 Note
pan-tropical distribution.
Figure 2. Justicia californica, specimen
LMARKOV16. Top Perianth. Note bilabiate,
sympetalous corolla. Bottom Ovary
Cross-section. Note 2 locules with one ovule per
locule, and axile placentation.
Exemplar Description Justicia californica
(Benth.) D. Gibson L. Markovchick-Nicholls.
LMARKOV16, SDSU. See Figures 1-5. Floral
formula K (5) C (5) A 2 G (2), superior,
hypogynous.
Plant a terrestrial, perennial, hermaphroditic,
shrub, 0.3 to 2 m tall tall. Aerial stem erect,
caulescent. Twigs puberulent. Thorns, spines,
prickles, and spur shoots absent. Leaves simple,
petiolate, stipulate, drought deciduous,
opposite, decussate, inclined, slightly recurved
and conduplicate. Petioles terete, green, 5-10mm
long, inclined. Stipules adaxially and abaxially
puberulent, 1 mm long. Leaf blade light green to
dark green, ovate to triangular, 1.5-2.5 cm long,
1-1.5 cm wide, rounded to cordate, entire to
sparsely serrate, acute to cuspidate,
pinnate-netted, puberulent, with veins slightly
protruding. Inflorescence terminal, bracteate,
raceme, 8-13 cm long, 5-6 cm wide from corolla
apex to corrolla apex, inclined, bisexual /
hermaphroditic, puberulent. Inflorescence bracts
basal, 8-9 mm long, light green, petiolate,
narrowly elliptic, cuneate, entire, acute to
acuminate, adaxially and abaxially puberulent.
Flowers perfect, caducous, 3.5 cm long, 5 mm
wide, opposite, inclined to ascending,
zygomorphic, pedicellate. Pedicel 8-9 mm long,
terete. Flower bracts caducous, basal, 8-9 mm
long, light green, petiolate, narrowly elliptic,
cuneate, entire, acute to acuminate, adaxially
and abaxially puberulent. Hypanthium absent.
Perianth dichlamydeous. Calyx valvate,
synsepalous (deeply lobed but fused at base),
radial, 5-9 mm long, green to purple-brown,
adaxially and abaxially puberulent.
Sepals 5, 4-5 mm long, narrowly triangular,
fused, entire, acute. Corolla bilabiate to
cucullate, valvate, sympetalous, dark red with
streaks of yellow in center, zygomorphic, 2-4 cm
long, puberulent, prominent veins, with 2
becoming stamens. Petals 2 lips, but 5 lobes,
fused, entire, rounded, 13-15 mm long, inclined,
anterior lip cernuous to squarrose. Stamens
uniseriate, 2, filamentous, epipetalous, whorled,
inserted, epipetalous. Staminodes absent.
Filaments terete, yellowish, 15-20 mm long.
Anthers basifixed, dithecal, longitudinal, red,
3-4 mm long, narrowly elliptic, and dehisce
downward, with thecae offset. Pollen yellow.
Gynoecium syncarpous. Perianth/androecial
position hypogynous. Ovary superior, green, 3-3.5
mm long, ellipticoid, but irregular and bumpy,
puberulent at base. Style 1, terminal, linear,
dark pink to dark red, inclined, straight with
corrolla attached, coiled when corolla falls off.
Stigma 1, terminal, globose, viscid. Single
donut-shaped nectariferous disk at bottom of
ovary. Carpels 2. Locules 2. Placentation
axile. Ovule 1 per carpel. Fruit a 2-valved
capsule, green, ellipticoid, but irregular and
bumpy, 10 mm long, 5 mm wide, puberulent.
Palynology Pollen reticulate and tricolporate,
but with several (14) distinctive circular
regions in two rows down the center of the axis
of the aperture. Aperture trident-shaped at
ends. See Fig. 4.
Figure 3. Stamen note inserted nature,
puberulent filament, and offset thecae.
Figure 5. Ovary, nectary, and style Note
donut-shaped nectariferous disk at base of
superior ovary, and coiled style after corolla
falls off.
Figure 4. Pollen and aperture Note reticulate
sculpturing and distinctive aperture.

Filament curtain common
Stamens reduced to 2, hygroscopic seed hairs
absent
4 mono-thecal anthers
Phylogenetic Relationships
Explosively dehiscent fruit
The Acanthus family are part of the Lamiales.
They are known to be differentiated from close
sister taxa (Near Out-Groups in Figure 6) by
their explosively dehiscent loculicidal capsules.
Within the family, there are four major lineages
(depicted in Figure 6). The Acanthus lineage are
distinct in having 4 monothecous stamens (McDade
Moody 1999). The Justicia lineage are often
marked by a reduction of the androecium to 2
fertile stamens (see exemplar description) and
also seem to lack the hygroscopic hairs present
on seeds of the Barleria and Ruellia lineages
(McDade Moody 1999). The Barleria and Ruellia
lineages also have corolla aestivation types
unique within the family, quincuncial and left
contort ( in contrast to imbricate or convolute,
McDade Moody 1999). Relationships among the
family and sister taxa are still commonly
debated. For instance, those listed as Near
Out-Groups in Figure 6 were thought to be part
of the Acanthaceae until recently (McDade et al.
2000). In some genera a curtain of filaments
covers the nectary (see Figure 7 top),
hypothesized to prevent nectar evaporation,
function in depositing pollen on visiting
insects, increase stability and precision of
pollination mechanisms in large flowers, or
restrict nectar access. The specific form or
type of filament curtain (Figure 7, bottom)
appears to be useful in discriminating among
members of the Ruellia lineage (Manktelow 2000).
Figure 7. Filament curtain from Maktelow 2000.
Top Curtain of filaments shields nectary.
Bottom Four types of filament curtains in
Ruellia lineage.
Figure 6. Acanthaceae Cladogram from McDade et
al. 2000. Note close relatives and 4 main
lineages.
McDade, L. A. and Michael Moody. 1999.
Phylogenetic relationships among Acanthaceae
Evidence from Noncoding trnL-trnF chloroplast DNA
sequences. American Journal of Botany 86 (1)
70-80. McDade, L. A., S. E. Masta, Michael L.
Moody, and Elizabeth Waters. 2000. Phylogenetic
relationships among Acanthaceae Evidence from
two genomes. Systematic Botany 25(1)
106-121. Stevens, P.F. 2001 onwards.
Angiosperm Phylogeny Website. Version 6, May
2005 and updated continuously since.
http//www.mobot.org/MOBOT/research/APweb/. Simps
on, Michael G. (2006). Plant Systematics.
Elsevier Academic Press, San Diego. Thongsaard,
Watchareewan, Charles A Marsden, Peter Morris,
Malcolm Prior, Yasmene B. Shah. 2005. Effect of
Thunbergia laurifolia, a Thai natural product
used to treat drug addiction, on cerebral
activity detected by functional magnetic
resonance imaging in the rat. Psychopharmacology
180 (4) 752-760.
Literature Cited
Chen, Fu-An, An-Bang Wu, Pochuen Shieh,
Daih-Huang Kuo, and Chi-Ying Hsieh. 2006.
Evaluation of the antioxidant activity of Ruellia
tuberose. Food Chemistry 94 (1)
14-18. Heywood, V.H. 1985. Flowering plants of
the world. Prentice Hall, Englewood Cliffs, NJ.
Hickman, James C. (ed). 1993. The Jepson
Manual Higher Plants of California. University
of California Press, Los Angeles. Manktelow, M.
2000. The filament curtain a structure
important to systematics and pollination biology
in the Acanthaceae. Botanical Journal of the
Linnean Society 133 129-160.