Heliamphora

Abstract: Sarraceniaceae, a New World family of carnivorous plants, consist of Sarracenia, Heliamphora, and the monotypic Darlingtonia. Despite extensive interest in these plants, few explicit phylogenetic hypotheses are available for the family. We investigate phylogenetic relationships in the family using sequences of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS) and of the chloroplast gene rbcL. One representative of each genus was sequenced for rbcL, whereas representatives of all species in the family, except for H. heterodoxa and H. ionasii, were sequenced for ITS. Both the ITSand rbcL-based phylogenies demonstrate that Sarracenia and Heliamphora form a monophyletic group that is the sister group of Darlingtonia. Sarracenia and Heliamphora are each well supported monophyletic genera. In our restricted sampling of Heliamphora, H. nutans is the sister of H. minor and H. tatei. Our results provide little resolution of relationships among species of Sarracenia, but identify one clade that consists of all species except S. alata. Within this clade are two smaller clades comprising:-1) S. purpurea and S. leucophylla,-and-2) S. flava, S. minor, and S. psittacina. Sarraceniaceae have received considerable attention from biologists because of carnivory throughout the family. All members of Sarraceniaceae are found in nutrient-poor habitats and like other carnivorous plants use animals as a supplemental source of nitrogen that is taken up in the form of ammonia (Christensen 1977; Bradshaw and Creelman 1984; Jaffe et al. 1992). Sarraceniaceae, Cephalotaceae, and Nepenthaceae use pitcher-like (ascidiate) leaves as passive traps for the collection of animals. As has been suggested previously (Thanikaimoni and Vasanthy 1972; DeBuhr 1975) and shown in recent phylogenetic analyses (Albert et al. 1992; Chase et al. 1993), the ascidiate leaves shared by these three families are evolutionary parallel-

Abstract: A B S T R A C T Scanning electron microscopy was used to observe features of representative species of the five carnivorous pitcher plant genera which allow them to lure, capture, and digest insects. Nepenthes rafflesiana, Sarracenia purpurea, Darlingtonia californica, Heliamphora heterodoxa, and Cephalotus follicularis were studied. The many morphological similarities observed in the phylogenetically unrelated plants show evidence supporting the concept of their convergent evolution. Several previously undescribed features of some plants were resolved which help elucidate their insect trapping mechanisms. THE SCANNING ELECTRON microscope (SEM) has been used to observe many features of the actively insectivorous Venus's fly trap [Dionaea muscipula Ellis (Droseraceae)] which allow it to lure, capture, and digest insects (Mozingo, et al., 1970). However, few such observations have been made of the analogous features of the passively insectivorous pitcher plants, other than Sarracenia (Panessa and Gennaro, 1972; Barckhaus and Weinert, 1974; Panessa, et al., 1976). The five genera of pitcher plants [Nepenthes (Nepenthaceae); Sarracenia, Darlingtonia, Heliamphora (Sarraceniaceae); Cephalatus (Cephalotaceae)] trap insects passively by means of hollow leaves or leaf appendages termed "pitchers." At the top of the pitcher are nectar glands which attract insects to the pitcher. The structure of the pitcher and gland placement induce attracted insects to enter the pitcher, and once inside this "pitfall" trap (Lloyd, 1942), the insect is prevented from escaping by various features of the pitcher. Captured insects drown in the liquid contained at the bottom of the pitcher and are digested by bacteria, or in some cases by a pepsin-like enzyme secreted by digestive glands.

Abstract: Examination ofHeliamphora heterodoxa andH. tatei from the Guayana Highlands of Venezuela reveals that the enol diacetal monoterpene, sarracenin, is the major volatile compound present in the spoon-shaped structures of leaves of the pitchers. In addition, erucamide, phenol, cinerone, phenylacetaldehyde, and a series of methyl esters also occur in extracts of the spoon-shaped appendages of pitchers at the time during which they attract insects.