Miscellaneous Disciplines 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 (Tarasevich, 1989).

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).