that Played an Important Role in the History of Aroid Research
It is not the intent
of this paper to cover all disciplines that have affected our
understanding of Araceae. However, some specialized researchers
made discoveries that have greatly enhanced our understanding
of the taxonomy and evolution of the family.
Papers dealing with fossils,
though often individually not important should be mentioned because
of their relative importance to the study of evolution of Araceae.
Among them are papers by Madison & Tiffney (1976), Bogner
(1976c), Gregor & Bogner (1984, 1989), Dilcher & Daghlian
(1977), and (Stockey et al., 1997).
In the field of vegetative
and floral anatomy of aroids, the works of P. van Tieghem (1867,
1872, 1885), H. Solereder (1919), and Solereder & F. J. Meyer
(1928) are noteworthy, as are those of M. Lierau (1887, 1888)
on roots, M. Dalitzsch (1886) on leaf anatomy, and E. Daumann
(1931) on nectar production. Engler, no doubt, built on these
extensive anatomical studies and more recent morphological studies
of floral anatomy by Eyde et al. (1967), Carvell, Barabé,
and Blanc (see above) and studies with fruits and seeds (Martius,
1831; Krishnamurthi & Geetha, 1986; Kulkarni et al.,
1990; Seubert, 1993) have also been important in helping to define
relationships in the family. [See also the discussion of the important
anatomical work by J. C. French.]
Developmental and embryological
studies have been comprehensive. Embryological studies have been
made by D. H. Campbell (1900, 1903, 1912) and F. J. Jüssen
(1929), and systematically important aspects of embryology were
reviewed by Grayum (1985, 1986a). James Gow (1908) made developmental
studies on a variety of genera, followed by a paper attempting
to define phylogeny in the Araceae (Gow, 1913a, 1913b) [see also
Barabé, Blanc, and Ray above]. Other studies of growth
behavior have been made on Philodendron (Ritterbusch, 1971)
and Symplocarpus and Lysichiton (Rosendahl, 1911).
Hans-Jürgen Tillich, from Germany, has carried out extensive
surveys of the structure and growth behavior of seedlings of Araceae
as a part of his broader survey (Tillich, 1985). Also, M. Möbius
(1936) published a brief review of vegetative reproduction.
Molecular studies have
been done on the economically useful genera Colocasia and
Alocasia by H. Yoshino (1975, 1994, 1995, in press) in
Japan and China. (See also section above on James French.) Papers
critical to the understanding of the evolution of the Araceae
are molecular studies of rbcL in the Liliiflorae (Chase &
Albert, 1995) and among all monocots (Duvall et al., 1993).
A recent molecular study appears to establish the Lemnaceae along
with the genus Pistia to form a monophylletic group within
the Araceae (Stockey et al., 1997).
There have been numerous
studies on chromosomes of Araceae. In England, C. J. Marchant
conducted an important series of cytological studies throughout
much of the 1970's (Marchant, 1970, 1971a, 1971b, 1972, 1973,
1974). His section by section treatment and discussion of cytology
is one of the earliest attempts to understand the Araceae cytologically.
His cytological work was preceeded by others, who though not dealing
specifically with Araceae, did a great deal of cytological work
with the Araceae. Among these researchers are G. E. Jones in the
United States (Jones, 1957), P. Pfitzer (Pfitzer, 1957) in Germany,
and several other cytologists, especially in India. Principal
among the Indian cytologists is A. K. Sharma and his collaborators.
Their papers deal with a study of karyotypes (Sharma & Das,
1954), the cytological evolution of Aglaonema and Richardia
[= Zantedeschia] (Sharma & Datta, 1961), a cytological
study on Philodendron and Monstera (Sharma &
Mukhopadhyay, 1964), on Arisaema and Typhonium (Sharma
& Mukhopadhyay, 1965) and on eight genera in five tribes (Sharma
& Bhattacharya, 1968). Other cytological work was carried
out by A. Mookerjea who attempted to trace the evolution of a
number of genera of Araceae (Mookerjea, 1955). Both K. Ramachandran
(1977, 1978) and K. S. Patil (Patil & Dixit, 1995) did studies
on Indian Araceae.
Reviews of the cytology
of the Araceae were made by C. J. Marchant (1970, 1971a, 1971b,
1972, 1973, 1974), and the cytology of Anthurium has been
recently summarized by Sheffer (Sheffer & Croat, 1983) and
for the whole family by Gitte Petersen of Copenhagen. Petersen
did a thorough review of the cytology of the Araceae for her Masters
thesis as well as in other subsequent cytological work (Petersen,
1989, 1993a, 1993b; Petersen, unpublished). Kai Larsen, at the
University of Aarhus, did a revision of the cytology of the aroids
of Thailand (Larsen, 1969).
Michael H. Grayum has
recently reviewed the palynology of the Araceae (Grayum, 1984,
1990). In addition to Grayum's study there have been other major
and some minor palynological studies on the Araceae. One of the
first thorough studies that preceded Grayum was a light microscopic
study of Araceae pollen by the late G. Thanikaimoni (1969) of
India. Ohashi et al. (1983; J. Murata & Ohashi, 1984)
reviewed the pollen morphology of Arisaema. M. Zavada made
an extensive comparative study on aroid pollen, especially involving
evolutionary trends of apertures and wall structures (Zavada,
1983). A review of the pollen of Amorphophallus and Pseudodracontium
was made by van der Ham, Hetterscheid and van Heuven (Ham et
al., 1998). Daniel Beath, from England, has a principal interest
in pollination of Araceae and has completed a study on Amorphophallus
in Ghana (Beath, 1996), and on beetle pollination in Dieffenbachia
longispatha (Beath, 1999). Current work on palynology is being
carried out by V. F. Tarasevich at the Komarov Botanical Institute.
She has published a SEM study of 34 species of Anthurium
Chemical aspects of Araceae
have been reviewed by Hegnauer (Hegnauer, 1963, 1986, 1987) and
more recently by Dring and his associates at the Jodrell Laboratory
at Kew (Dring et al., 1995).
Studies on pollination
biology of Araceae are numerous and have been reviewed elsewhere
(Grayum, 1986c, 1990; Bay 1995). K. Dormer (1960) wrote on pollination
in Arum. Y. Mori and H. Okada (in press) reported on reproductive
biology and pollen flow of Furtadoa. Most have dealt with
the physiological phenomenon of thermogenesis (Walker et al.,
1983) and only indirectly with pollination (Uemura et al.,
1993). No attempt will be made here to review all of the literature
on pollination biology of Araceae but some of the more recent
and thus not previously reviewed papers dealing with the subject
will be mentioned here. A recent paper (Patt et. al., 1995) discusses
the brood-site-based pollination system of Peltandra virginica
in eastern North America. The work also serves as the debut of
Jim French, one of the co-authors, into work with pollination
systems. Pollination strategies were studied in Brazilian species
of Philodendron (Gottsberger & Amaral, 1984).
A major review work on
P-type sieve-element plastids of all the Arales (Behnke, 1995)
provides new evidence for the inter-relationship of the Araceae
to other closely related monocots and for the subgeneric classification
of the family.
Finally, other general
papers dealing with phylogeny are critical to the understanding
of the evolution and general placement of the Araceae among the
monocotyledons. Some of these are: Takhtajan (1969, 1980, 1997);
Thorne (1968, 1976, 1983); Hutchinson (1973); Cronquist (1981);
and Dahlgren & Rassmussen (1983).