Reevaluation of Mimosa biuncifera and M. texana (Leguminosae: Mimosoideae)

Mimosa biuncifera, as currently defined in southwestern United States, is shown to comprise two related species,M. biuncifera s. str. andM. texana, distinguished primarily by position of the nodal aculei. Taxonomic synonyms ofM. biuncifera areM. lindheimeri andM. warnockii (the first undisputed, the second provisional);M. texana includesM. wherryana.     

A phylogenetic analysis ofLeucaena (Leguminosae: Mimosoideae)

Chloroplast DNA restriction fragment length polymorphisms have been used to reconstruct the maternal phylogeny of all the known taxa in the small neotropical legume genusLeucaena. Three major plastome clades were recognized, but these did not conform with relationships between the taxa proposed on other characters from morphology, cytology or hybridization. The maternal parentage of tetraploids within the genus has been proposed. Evidence for introgression was found between diploidL. diversifolia and tetraploidL. diversifolia. The implications of these results for the origin of the cultivated taxa are discussed.     

Seasonality of some Chihuahuan Desert soil oribatid mites (Acari: Cryptostigmata)

1. Reproductive strategies of four species of oribatid mites were investigated in the Chihuahuan Desert from 1981 to 1984.
2. Breeding activity coincided with the summer rainfall period in three of the four cases: Passalozetes neomexicanus, P. californicus and Jornadia larreae. This pattern was not changed by the application of simulated rainfall at other times of the year. The strict seasonality of reproductive behaviour is interpreted as an outcome of strong selection pressure to recruit only when food quality and quantity and microclimate are most favourable.
3. Joshuella striata showed a more flexible pattern which was essentially bimodal. Periods of egg production occurred in winter and also during the summer rainfall period. This pattern is consistent with the known distribution of this species in winter- and summer-rainfall deserts in south-western USA.     

Isozyme variation inFaidherbia albida (Leguminosae, Mimosoideae)

Genetic variation has been assessed in 30 populations (931 families) ofFaidherbia albida (Leguminosae, Mimosoideae) from across its entire African range, using six isozyme loci identified by five enzyme systems. Among the populations studied a null allele was proposed to explain the absence ofLap-1 activity in populations from southern and eastern Africa. The mean percentage of polymorphic loci per population, the mean number of alleles per locus and the mean genetic diversity within populations were 31.7%, 1.6 and 0.127 respectively. Genetic diversity was greatest in populations from West Africa and lowest in populations from eastern/southern Africa, with Ethiopian/Sudanese populations intermediate. The overall degree of genetic differentiation between populations (G_ST) indicated that approximately 56% of the enzyme variation resided within populations. Clustering of Nei's unbaised genetic distances calculated between all populations produced a dendrogram that generally followed the geographic distribution of the populations. Two major groups were identified that may be considered the eastern/southern African and the Ethiopian/West African clusters. Within the Ethiopian/West African cluster two subclusters could be recognised, one broadly corresponding to those populations from Ethiopia/Sudan and the other to those populations from West Africa. The implications of these results for theories regarding the origin ofF. albida in Africa are discussed.     

The genus Archidendron (Leguminosae – Mimosoideae)

An account is given of the morphology and the taxonomy of the Asian, Australian and Pacific genus Archidendron (Leguminosae – Mimosoideae). A new infrageneric classification based on morphological data is presented, the genus being subdivided in 8 series. The phylogeny of the genus is discussed, the base of discussion being all available morphological, palynological and wood–anatomical characters. The presence/absence of stipules, the length of the staminal tube compared with that of the corolla–tube, the sessile/stipitate ovary(–ies), the morphology of the pods and the wood–anatomy have been particularly useful in determining the evolutionary trends within the genus. Analyses of the geographical range of selected character states are presented. The data suggest a Central – W. Malesian origin of the genus. The series endemic to the E. Malesian – Australian area have probably evolved more recently. The pluricarpellate condition of the flowers in several species endemic to the E. Malesian and Australian area is considered to be a derived character state. The following new taxa are proposed: Ser. Calycinae Nielsen, ser. Ptenopae Nielsen, ser. Bellae Nielsen, Archidendron falcatum Nielsen, A. cockburnii Nielsen, A. sabahense Nielsen, A. fagifolium (Bl. ex Miq.) Nielsen var. borneense Nielsen, A. kunsrteri (Prain) Nielsen subsp. ashtonii Nielsen, A. ellipticum (Bl.) Nielsen subsp. cordifoliolatum Nielsen. New combinations are proposed in the Malesian species formerly referred to Abarema, Zygia and Morolobium by Kostermans. Keys to and an enumeration of the species are presented.     

Cotyledon architecture and anatomy in the Acacieae (Leguminosae: Mimosoideae)

Cotyledon size, shape, venation pattern and anatomy have been investigated in Faidherbia albida and 152 species of Acacia representing the three subgenera Acacia, Aculeiferum and Heterophyllum. Cell volumes of epidermis, palisade and storage tissue, stomatal frequency, stomatal index and frequency of stomatal types have been determined for F. albida and 12 species from each subgenus. The data obtained support the recognition of the subgenera of Acacia as separate taxa but provide no indication of their status. The evidence from cotyledons also supports the separation of Faidherbia from Acacia , and the amalgamation of the Acacieae and Ingeae.     

Acacia sousae (Leguminosae: Mimosoideae) a new species from Mexico

A new species,Acacia sousae, from the states of Guerrero and Puebla is described and illustrated. A key for determination of the related species is given.     

Polyploidy in Dalea formosa (Fabaceae) on the Chihuahuan Desert

Dalea formosa consists of diploids (n = 7), tetraploids (n = 14), and hexaploids (n = 21), the polyploids restricted to the Chihuahuan Desert region or its immediate borders. There is very little morphological differentiation between the three chromosome races and, therefore, the polyploids are assumed to be primarily autoploid. Tetraploids discovered were few and were very similar to hexaploids; the two ploidy levels were combined as “polyploids” for analyses of geographically and cytologically correlated morphological variation. Pollen length generally was found to be greater in known polyploids than in known diploids. Through the use of pollen length and geographic origin, chromosomally unknown specimens were estimated as to ploidy level. This produced four groups, known diploids and polyploids, and putative diploids and polyploids, which were then subjected to stepwise discriminant analysis (SDA) to search for other morphological characters that might indicate ploidy level, to evaluate the assignments to putative ploidy level in unknown plants, and to assess correlation of these plants of putative ploidy level to geographic regions. SDA also indicated that pollen length, among ten morphological features, is the primary discriminator between ploidy levels, and that putative polyploids are confined primarily to the Chihuahuan Desert. Chromosomally unknown specimens that were originally assigned to one ploidy level, but were classified by SDA as another, are viewed as indicative of areas where further cytological sampling is particularly needed. These areas are southeastern Arizona, where pollen among known diploids is comparatively large, northeastern New Mexico, where polyploids might occur off the Chihuahuan Desert, east edge of the Chihuahuan Desert in Texas, a cytologically poorly sampled contact zone between diploids and polyploids, and central Coahuila, where no cytological sampling has been done. Canonical variate analysis is used to aid in the visualization of the general morphological relationship between diploids and polyploids.     

Studies in Stryphnodendron (Leguminosae: Mimosoideae) including two new taxa

Stryphnodendron campestre Forero andS. guianense (Aubl.) Benth. ssp.glandulosum Forero are described and illustrated, and notes on the nomenclature ofS. adstringens and on the exclusion ofS. colombianum from the genus are included.     

Cotyledon venation patterns in the Leguminosae: Mimosoideae

Cotyledon venation patterns are described for 131 species representing the four main tribes of the Mimosoideae. The range of variation in venation pattern falls within that described previously for the Caesalpinioideae and is consistent with the proposal that all patterns in the Leguminosae have been derived from a prototype with four vascular strands and a protoxylem trace in the petiole and seven primary veins in the lamina. Each tribe is characterized by a particular set of patterns, pattern frequencies and evolutionary trends. In the Mimoseae, correlations between venation pattern and cotyledon size and anatomy match those found in the Caesalpinioideae, but different correlations unique to these tribes occur in the Acacieae and Ingeae.     

Analysis of the genetic similarities among seven species of Prosopis (Leguminosae:Mimosoideae)

Summary Prosopis (mesquite) is a commercially promising plant genus that has received increased attention lately. Allelic frequencies at 25 enzyme loci in seven species from the section Algarobia were transformed in matrices of genetic distance using three methods. The indices give highly correlated results; only in the cluster Prosopis alba -P. hassleri were minor discrepancies evident. The phenetic relationships observed agree with other biochemical evidence (chromatography of phenol compounds, electrophoresis of seed proteins, etc) but not with morphological groupings. The present data support the hypothesis that the species belonging to the section Algarobia would be equivalent to sub- or semispecies; the community of such sympatric subspecies constitutes a syngameon.     

A second spontaneous hybrid in the genusLeucaena (Leguminosae, Mimosoideae)

The detection of hybridity inLeucaena is discussed in relation to: (i) traditional criteria, (ii) molecular criteria and (iii) models to predict hybrid leaf morphology. Morphological, geographical and molecular evidence for the occurrence of interspecific hybrids betweenL. leucocephala andL. diversifolia in south-central Mexico, northern Guatemala, Jamaica, Dominican Republic, the Philippines and Papua New Guinea is presented. Predicted mean hybrid leaf trait values calculated from parent material are compared with data from putative hybrids and shown to be similar. The origin of these hybrids is discussed and shown to be the result of artificial sympatry resulting from indigenous, and recent exotic, domestication of the parent species. The hybrid is described asL. ×spontanea.     

Unusual diversities of seed beetles (Goleoptera: Bruchidae) on Parkia (Leguminosae: Mimosoideae) in Brazil

Earlier studies of the interrelationships between bruchid beetles and their host plants have suggested that the typical pattern tends to be that one bruchid species attacks only a few host species, and that most host species are attacked by only one bruchid species, or at most very few. However, the bruchids attacking Parkia in Amazonian Brazil do not conform to this pattern. The bruchid diversity on Parkia was found to be higher than on any other legume genus yet studied. It is not yet possible to assess whether Parkia is particularly unusual in this regard, or whether such high levels of diversity are typical in Amazonian forests. The number of bruchid taxa attacking any one Parkia species is related to the number of co-occurring closely-related Parkia species. In either taxonomically or geographically isolated host species the bruchid diversity is much reduced.     

中国鸡头薯属的分类学研究

通过对中国鸡头薯属大量标本的比较研究,作者认为种Eriosemahimalensis不能成立,应将其降为Eriosemachinensis的异名。本文还绘制了鸡头薯块根的形态变异图,作为进行分类学处理的重要依据之一。     

Three new species of Parkia (Leguminosae: Mimosoideae) from tropical South America

Parkia cachimboensis andP. bahiae are described from central and eastern Brazil respectively. The third new species,P. panurensis, which is widespread in central and western Amazonia, has passed hitherto under the incorrect nameP. pectinata (Willd.) Benth.     

Interspecific compatibility among 15 Leucaena species (Leguminosae: Mimosoideae) via artificial hybridizations

Leucaenas are fast-growing neotropical trees and shrubs used as forage and fuelwood. This study tested the seed crosscompatibilities among 15 of the 16 well-defined species of the paleopolyploid genus Leucaena Bentham (Leguminosae: Mimosoideae) to determine if genes of interest could be transferred between species. Twelve diploid and four tetraploid taxa were artificially hybridized in 118 of all 120 possible two-way combinations and 31 of 32 possible self- and intraspecific matings, with 58,218 floret pollinations. Ninety-one combinations (77%) produced well-filled seed, and 73 of these combinations were grown and validated in the field. The qualitative crossability within ploidy levels (diploid, triploid, tetraploid) was 78%, 75%, and 100%, respectively, whereas quantitative crossability (relative to intraspecific matings) of successful matings within identical ploidy levels was 32%, 11%, and 73%, respectively. One-third (34%) of the 114 interspecific combinations tested in both directions exhibited weak unilateral incompatibility (UI), due, in part, to reciprocal differences in stylar length. Other mechanisms for UI (embryo-endosperm imbalance, sex-specific use of self-compatible parents) were ruled out. Wide hybridization appears to be “buffered” by polyploidy in the genus.     

Metamerism,heterochrony, and inflorescence morphology of the Pithecellobium-complex (Leguminosae: Mimosoideae: Ingeae)

The diverse inflorescence morphology of species in the Pithecellobium-complex is shown to be a result of: 1) the organization of the components of the inflorescence and their relative positions; 2) the hierarchical relationship of the axes of the inflorescences and the position they assume in total tree architecture; and 3) heterochronic development of the components of the inflorescence. It is shown that the typological system of nomenclature of inflorescences leads to false assumptions of homology and therefore must be discarded. The morphology of inflorescences is discussed in terms of metamerism, and the term Repeating Growth Unit (RGU) is introduced and is defined as the smallest complete sequence of metamers produced by a meristem. A module is defined as the sequence of RGUs produced by a meristem. An inflorescence is defined as that sequence of metamers in an RGU which participates in the production and/or presentation of flowers and fruit. Heterochrony, proleptic and sylleptic buds, and shoot dimorphism are discussed and their role in modifying inflorescence morphology in the Pithecellobium-complex is illustrated. Examples from the Pithecellobium-complex are provided which demonstrate the various modifications of the inflorescence that result from the interaction of these various phenomena.     

Nomenclatural Notes on Cassia Linnaeus (Leguminosae: Caesalpinioideae)

Arguments are developed in favor of changed names for 4 common American cassias; if accepted,C. tagera auct. (vix Linnaeus) becomesC. kunthiana Chamisso & Schlechtendahl ;C. fasciculata Michaux becomes C.chamaecrhta Linnaeus;C. hispidula Vahl becomesC. tetraphylla Martyn; andC. tetraphylla Desvaux becomesC. desvauxii Colladon.     

Argentinean native wood species: Physical and mechanical characterization of some Prosopis species and Acacia aroma (Leguminosae; Mimosoideae)

One of the problems in marketing the wood of Prosopis and Acacia is the lack of standardization of its qualities. The aim of this paper was to obtain a preliminary detection of some properties of the wood of four species of the genus Prosopis and one species from Acacia grown in Argentina. To accomplish this objective, the content of extractives and some physical and mechanical characteristics were analyzed.The density ρ₁₂ of all the species indicates that these woods range from heavy to very heavy (?0.69 g/cm³). The total volumetric shrinkage values are low, less than 10%, for all species. The parallel compression strength and the shear strength for all the species indicate a very resistant wood (?46.93 MPa and ?18.35 MPa, respectively). Brinell hardness was higher than 5 kg/mm² in all cases. The species with less content of extractives is P. ruscifolia (approximately 9% of anhydrous mass) whereas A. aroma was the one with the greatest content (approximately 25% of anhydrous mass in the heartwood).     

Systematics and randomly amplified polymorphic DNA in the genusLeucaena (Leguminosae,Mimosoideae)

Randomly amplified polymorphic DNA (RAPD) was used to examine genomic diversity in taxa of the neotropical legume genusLeucaena. Data were analysed using both similarity- and parsimony-based approaches and the data compared to a parsimonybased analysis of chloroplast DNA restriction fragment length polymorphisms (RFLP). Distance-based methods of RAPD analysis produced groups inconsistent with those identified by RFLP analysis. Parsimony-based analysis of the data produced groupings largely consistent with those identified using RFLPs. The major differences were grouping of the two subspecies ofLeucaena diversifolia (subsp.diversifolia and subsp.stenocarpa) in the RAPD tree, but their separation in the RFLP tree. The value of RAPD data in systematics as a result of these data and our understanding of the molecular basis of RAPDs are discussed.