Barclaya

Abstract: Definition of some vascular plant families is unsatisfactory and, consequently, it is impossible to classify them adequately. The lack of an analytical key to the families based on easily observed, widespread characters sometimes results in surprising misinterpretations. A striking example in this regard is the Casuarinaceae. Engler (1897) considered them to be true Angiospermae (Dicotyledoneae, Order 1. Verticillatae). Melchior (Engler's Syllabus der Pflanzenfamilien, vol. 2. 1964) and Wettstein (1935) concur with Engler, but Hutchinson (1973) placed the Casuarinales (Order 18) between the Juglandales and Urticales. According to Takhtajan (1969, 1973) the Casuarinaceae probably arose from the Hamamelidales. Gaussen (1940) derived the Casuarinaceae from the Articulatae. Hegnauer (1964) recalls that authors have noted similarities between Casuarina, Equisetum, Ephedra, and the Coniferae, but states the chemistry of the family is not well enough known to determine its position in the system. The Nymphaeaceae is another difficult family to place in the system. In Engler's Syllabus, Order 16 Ranunculales includes the suborders Ranunculineae and Nymphaeineae. The latter contains families Nymphaeaceae, and Ceratophyllaceae. The first of these is divided into the subfamilies Cabomboideae, Nymphaeoideae and Nelumbonoideae. Wettstein places the Nymphaeaceae in Order 18, Polycarpicae, following Family 20, Berberidaceae. The Nymphaeaceae contains the same subfamilies as in Engler's Syllabus. The following family is Ceratophyllaceae, which is considered closely related to the Nymphaeaceae. Hegnauer (1969) states that the evidence is not sufficient to form an opinion with respect to the relationships of all the genera included in the Nymphaeaceae. Hutchinson puts the family in the Ranales and it includes Nelumbo, Euryale, Nuphar and Barclaya. He treats Cabombaceae and Ceratophyllaceae as separate families. According to Kubitzki (1972), the Nymphaeaceae, s. str., do not belong in the Polycarpicae. A third example is the Cyclanthaceae. Wettstein placed them in the Order Synanthae, with the Palmae and Araceae but the plants of the three families are very different. The Palmae are mostly derived, the Cyclanthaceae include at least two different plant types, and the Araceae, mostly herbaceous, exhibit distinctive features. In Engler's Syllabus, the Order Synanthae (Cyclanthales) comprises the family Cyclanthaceae with subfamilies Carludovicoideae and Cyclanthoideae. These are herbs of palm-like habit and deeply bilobed leaves. They are very old, reduced and derived relicts. Hegnauer considers the Palmae, Cyclanthaceae and Pandanaceae more closely related to one another than to the herbaceous Araceae, Typhaceae and Sparganiaceae. According to Takhtajan, the Arales, Arecales and Cyclanthales were derived from the immediate ancestors of the Liliales.