B-E. van Wyk

The major alkaloids of the genus Melolobium

The major alkaloids of 12 species of the genus Melolobium Eckl. & Zeyh. have been characterized. Variable quantities of anagyrine, camoensine, leontidine, lupanine, N -methylcytisine and thermopsine are present in nearly all of the extracts. Sparteine, cytisine and some unidentified alkaloids occur less frequently. If one species [ Melolobium involucratum (Thunb.) Stirton] is excluded, the genus is morphologically very uniform and also appears to be uniform in its alkaloidal metabolites. Within the tribe Crotalarieae, the combination of thermopsine and the two C 14 alkaloids leontidine and camoensine may prove to be a unique chemotaxonomic character for Melolobium.

Observations on the occurrence and distribution of alkaloids in some genera and species of the tribe Crotalarieae (Fabaceae)

A general survey of alkaloids in the tribe Crotalarieae showed that useful chemotaxonomic data may be obtained. Although the pyrrolizidine alkaloids of Crotalaria L. have been studied in considerable detail, virtually nothing is known for the other, predominantly southern African genera. The genera Dichilus DC., Lebeckia Thunb., Melolobium Eckl. & Zeyh. and Polhillia Stirton were found to contain several alkaloids in sufficient quantities to warrant further investigation. The major alkaloids (presumably all of the quinolizidine type) seem to be characteristic for each of these genera. Aspalathus L., Buchenroedera Eckl. & Zeyh., Lotononis (DC.) Eckl. & Zeyh., Pearsonia Duemmer, Rafnia Thunb. and Wiborgia Thunb. appear to produce much smaller amounts. The possibility of obtaining useful information from these genera seems limited in view of the large quantities of plant material required to enable proper identification of the compounds. Methods of extraction and detection are described. The R f values of the major alkaloids are given for the different thin-layer chromatographic systems used. Some preliminary identifications were confirmed by mass spectrometry.

Alkaloids of the genera Aspalathus, Rafnia and Wiborgia (Fabaceae – Crotalarieae)

The presence of alkaloids in three southern African genera of the tribe Crotalarieae is reported for the first time. Sparteine, lupanine and nuttalline were detected in several species of Aspalathus L., Rafnia Thunb. and Wiborgia Thunb., but rarely in more than trace quantities. Except for very large quantitative differences, the alkaloids are almost identical to those found in the genus Lebeckia Thunb. Available evidence suggests that the three genera are more closely related to Lebeckia than to any other genus of the tribe. The divergence of these genera seems to be linked to an almost total loss of the ability to produce alkaloids.

The Tribal Position of Hypocalyptus Thunberg (Fabaceae)

The tribal position of Hypocalyptus Thunberg in the Fabaceae subfamily Papilionoideae is investigated. A phylogenetic analysis in which the Australian Bossiaeeae and Mirbelieae, African Podalyrieae and Crotalarieae, South American Sophoreae and Millettieae, and northern temperate Thermopsideae and Genisteae are included, indicates that there is no direct relationship between Hypocalyptus and any of the tribes. It is therefore proposed that the monotypic subtribe Hypocalyptinae Yakovlev be raised to tribal level as Hypocalypteae (Yakovlev) A. L. Schutte. A description of the tribe is presented, followed by an enumeration of the three species recognized. Hypocalyptus Thunberg is a genus of papilionoid legumes confined to the Cape Floristic Region of South Africa. The genus is easily recognized by its trifoliolate leaves, magenta-pink flowers with a yellow nectar guide, intrusive calyx base, and fused stamens. It comprises three distinct species, which are restricted to the fynbos vegetation of the Western and Eastern Cape Provinces (Dahlgren, 1972). Despite its well-defined generic circumscription, the tribal affinities of Hypocalyptus have been uncertain ever since Benthams (1837, 1839) fundamental classification of the subfamily was published. This is clearly reflected in the number of times the genus has been transferred from one tribe or subtribe to another. Bentham (1837, 1839, 1844) placed the genus in the tribe Loteae subtribe Genistinae, which he later changed to the tribe Genisteae subtribe Cytisinae (Bentham, 1865). Harvey (1862) retained the genus in the Genisteae, recognizing no subtribes. In 1964 Hutchinson raised the Cytisinae to tribal level and allocated Hypocalyptus to the Cytiseae. Polhill (1976, 1981f) transferred the genus to the tribe Liparieae, which Yakovlev (1991) subdivided into the subtribes Lipariinae and Hypocalyptinae. He placed Hypocalyptus in the monotypic Hypocalyptinae. The problem regarding the tribal position of Hypocalyptus is thus quite evident. This has, in fact, also been pointed out by several authors (Dahlgren, 1972; Polhill, 1976, 1981e, 1994; Goldblatt, 1981; Bell et al., 1978; Van Wyk et al., 1994; Van Wyk & Schutte, 1995; Schutte & Van Wyk, 1997). As part of a taxonomic study of the tribes Podalyrieae and Liparieae, Schutte (1995) investigated the position of Hypocalyptus within the tribes. Morphological, anatomical, cytological, and chemical characters were examined and analyzed cladistically to determine interand infratribal relationships. The results clearly indicated that Hypocalyptus is misplaced in the Liparieae and should be excluded, while the Podalyrieae and remainder of the Liparieae are monophyletic and should be united (Schutte, 1995; Schutte & Van Wyk, 1997). Hypocalyptus deviates from the Podalyrieae (including the Liparieae) in no less than nine critical characters (Table 1). Of particular interest are the micromorphological characters, i.e., floral pigmentation (Van Wyk et al., 1994); the accumulation of canavanine in the seed (Bell et al., 1978); a chromosome base number of x = 10 (Goldblatt, 1981; Van Wyk & Schutte, 1995); and ephemeral antipodals in the female gametophyte (Schutte, 1997). These, in addition to the five macromorphological characters of the stamens, seed, and pods, indicate unambiguously that Hypocalyptus does not fit in the Podalyrieae. The aim of this paper is to examine the phylogenetic position of Hypocalyptus within the subfamily Papilionoideae. To this end we scanned the literature and selected all the tribes which are assumed to, or have previously been suggested to, be possibly related to the genus. Based on these criteria, the Australian Bossiaeeae and Mirbelieae, African Podalyrieae and Crotalarieae, northern temperate Genisteae and Thermopsideae, and South American Sophoreae and Millettieae were chosen as outgroups (see, e.g., Dahlgren, 1972; Polhill, 1976, 1981a, 1981g, 1994; Crisp & Weston, 1987). It is important to note that the primary objective of this study is to establish whether Hypocalyptus is directly related to any of the tribes, and not to analyze the relationships among the different tribes. NovoN 8: 178-182. 1998. This content downloaded from 157.55.39.177 on Sat, 19 Nov 2016 04:23:38 UTC All use subject to http://about.jstor.org/terms Volume 8, Number 2 1998 Schutte & van Wyk Tribal Position of Hypocalyptus 179 Table 1. Taxonomic differences between Hypocalyptus and the tribe Podalyrieae. Character Podalyrieae Hypocalyptus 1. Stamen fusion free to open sheath closed tube 2. Seed aril shape interrupted at the micropylar end continuous around the hilum 3. Micropyle type punctate y-shaped 4. Micropyle position within hilar region outside hilar region 5. Pods sessile stipitate 6. Chromosome base number x = 9 x = 10 7. Antipodals persistent ephemeral 8. Floral pigments esters of cyanidin-3-glucoside malvidin-3-glucoside 9. Canavanine absent present ANALYSIS AND RESULTS The data matrix, characters, and character states used for the tribal analysis are given in Table 2. These have largely been taken from Van Wyk and Schutte (1995), with some additions and alterations, e.g., the inclusion of Hypocalyptus as a separate taxonomic unit, the incorporation of the Millettieae and the omission of the Argyrolobium group (now included in the Genisteae; Van Wyk & Schutte, 1995). Data for the Australian Bossiaeeae and Mirbelieae came mainly from Polhill (1976, 1981c, 1981d) and Crisp and Weston (1987, 1995). Information on the Millettieae and Sophoreae has been taken from Geesink (1981) and Polhill (1981b), respectively. Polhill (1976) and Bisby (1981) were consulted for information on the Genisteae, and Turner (1981) for data on the Thermopsideae. Variation in the characters and polarization of character states are discussed in the references given at the end of each character. Where plesiomorphic and apomorphic states co-occur, the taxon was scored for the plesiomorphic state. Autapomorphies for the taxa were excluded from the analyses, since they serve no purpose as grouping char-

ONTOGENY OF THE FRUITS OF TWO ANOMALOUS AFRICAN WOODY GENERA, POLEMANNIOPSIS AND STEGANOTAENIA ( APIACEAE ), AND THEIR PHYLOGENETIC RELATIONSHIP

The fruits of two anomalous African woody Apiaceae, Polemanniopsis marlothii and Steganotaenia araliacea , differ in structure when mature though the ovaries are very similar, both being heteromorphic in young flower stage. This unexpected heteromorphism in S. araliacea has important implications for future studies of basal genera and the interpretation of fruit characters in general. Both taxa also have unique ‘intrajugal cavities’ in the ovaries and fruits, which supports the idea that the two genera are closely related, sharing some characters with the Hydrocotyloideae and Saniculoideae . This provides morphological and anatomical evidence to support the previous hypotheses on their relationship with Saniculoideae . Their basal position is also supported by characters shared with other basal genera previously included in Hydrocotyloideae , such as the lateral wings and slightly lignified endocarp in Polemanniopsis and Steganotaenia .

The major alkaloids of the genus Argyrolobium

The major alkaloids of 12 morphologically dissimilar species of Argyrolobium Eckl. & Zeyh. have been identified. All extracts contain large quantities of anagyrine as the dominant alkaloid. Cytisine, N-methylcytisine, lupanine, sparteine, 5,6-dehydrolupanine and ammodendrine are present as minor compounds in most of the species and as major compounds only in a few of them. The data do not reflect morphological dissimilarities and the species are remarkably uniform in their major alkaloids. Our conclusions are that Argyrolobium is closely related to the genus Polhillia Stirton, that large quantities of anagyrine may be taken as a chemotaxonomic marker for Argyrolobium and that a more detailed study of alkaloids may provide valuable taxonomic evidence in a genus without any obvious morphological specializations.

Unusual structural variation in the fruit of Dasispermum suffruticosum (Apiaceae): A new record of heteromorphic fruits in the family

Dasispermum is a monotypic genus found on sand-dunes along much of the South African coast. D. suffruticosum is exceptionally polymorphic in the structure of the fruit, and major morphological differences are found between fruits from different plants, which are not obviously correlated with geographic and taxonomic patterns. The mericarps vary from homomorphic to heteromorphic, the latter being a relatively rare condition in the Apiaceae and the occurrence of both types in the same species has not been reported before. In both the heteromorphic and homomorphic types, wing configuration is already evident in the flowering stage.

Taxonomic relationships in the genus Dichilus (Fabaceae — Crotalarieae)

Taxonomic relationships within the genus Dichilus have been investigated. A phenetic analysis of 25 different localities as OTU’s (five of each species) and 67 characters resulted in five distinct groups, corresponding to the five species that were recognized in a recent synopsis. For cladistic analyses, 15 characters were used and the genera Melolobium, Argyrolobium and Lebeckia were used as outgroups. In a further analysis the characters were intuitively polarized. Current cladistic methodology indicated only one fully resolved cladogram of minimal length, irrespective of the choice of outgroup. This cladogram is also supported by several additional characters and biogeographical evidence and is therefore proposed as the best estimate of the phylogeny of the species of Dichilus.

Chemotaxonomic significance of alkaloids in the genus Spartidium (Fabaceae — Crotalarieae)

The presence of alkaloids in the monotypic North African genus Spartidium Pomel is reported for the first time. Comparative GC and MS analyses showed that S. saharae (Coss.) Pomel contains the bipiperidyl compounds ammodendrine and N ′-formylammodendrine as major and minor alkaloids respectively. In addition, sparteine (a quinolizidine alkaloid) and two isomers of N -cinnamoylhistamine (an imidazole derivative) were present in small quantities. The morphological similarities between Spartidium and the genus Lebeckia Thunb. are not reflected in the alkaloid patterns. In Spartidium only a trace of one quinolizidine alkaloid was detected. Ammodendrine, the major Spartidium alkaloid, is absent or occurs only as a trace amount in Lebeckia. The results provide supporting evidence for Polhill’s (1976) decision to retain Spartidium as a distinct genus rather than to consider it a species of Lebeckia.

A New Species of the Genus Hermas (Apiaceae) from South Africa

A new species of the Cape endemic genus Hermas L. is described. Hermas proterantha B. J. de Villiers is a very distinct new species endemic to Piquetberg Mountain in Western Cape province. It is the only deciduous Hermas species and has thinly textured, deeply lobed (pinnatipartite) leaves that wither in summer.ABSTRACT A new species of the Cape endemic genus Hermas L. is described. Hermas proterantha B. J. de Villiers is a very distinct new species endemic to Piquetberg Mountain in Western Cape province. It is the only deciduous Hermas species and has thinly textured, deeply lobed (pinnatipartite) leaves that wither in summer.