Six new species of melampodium (compositae: Heliantheae) from Mexico and Central America

Six species of the genusMelampodium are described as new:M. glabribracteatum, M. nayaritense, andM. pilosum (sect.Melampodium);M. costaricense, M. nutans, andM. sinaloense (sect.Zarabellia). Chromosome numbers forM. nutans andM. pilosum are reported asn = 11 andn = 10 respectively     

Flavonoid chemistry of the endemic species of Myrceugenia (Myrtaceae) of the Juan Fernandez Islands and relatives in continental South America

Twenty-one flavonoids were isolated from the leaves of two endemic species ofMyrceugenia on the Juan Fernandez Islands,M. fernandeziana andM. schulzei, from two related species from Brazil,M. campestris andM. rufescens, and from five species from continental Chile,M. colchaguensis, M. exsucca, M. lanceolata, M. pinifolia, andM. rufa. A phenetic analysis was used to evaluate chemical similarities.Myrceugenia campestris andM. rufescens appear most closely related to each other based on flavonoid profiles, and they are also different from the other seven species. The two endemic species in the Juan Fernandez Islands,M. fernandeziana andM. schulzei, group with the continental Chilean species. The former is most closely related toM. lanceolata, and the latter clusters withM. exsucca, although somewhat distantly. The results suggest that the two Juan Fernandez endemics are derived from two introductions from the Chilean continent and not from immigrants from the eastern side of the Andes.     

Effect of mycorrhizae on seedlings of six endemic Mimosa L. species (Leguminosae–Mimosoideae) from the semi-arid Tehuacán–Cuicatlán Valley, Mexico

Mimosa is an important genus of legumes in arid and semi-arid ecosystems of the world, but scarce information is available about its interaction with microbial symbionts. In Mexico, there are no reports on the responsive of endemic Mimosa species to arbuscular mycorrhizal (AM) fungal colonization. In this study, the AM association with seedlings of six endemic Mimosa species, M. adenantheroides, M. calcicola, M. lacerata, M. luisana, M. polyantha and M. texana var. filipes, is reported. Field conditions were simulated in the greenhouse. Seeds were collected from plants and soil from the localities where the species occur within the semi-arid Tehuacán–Cuicatlán Valley, Mexico. Four treatments were applied: (1) control, (2) benomyl, (3) phosphorus, and (4) benomyl plus phosphorus. Mycorrhizal seedlings of five species, M. adenantheroides, M. lacerata, M. luisana, M. polyantha and M. texana var. filipes, showed a higher shoot and total dry weight than non-mycorrhizal seedlings. The only species that did not show any difference between mycorrhizal and non-mycorrhizal seedling performance was M. calcicola. M. luisana, M. polyantha and M. texana var. filipes had a higher root/shoot ratio; in general, benomyl treatments promoted seedling biomass allocation to the root, while control, phosphorus and benomyl plus phosphorus treatments decrease root/shoot ratio. Shoot P content was significantly higher in mycorrhizal than in non-mycorrhizal plants, although no significant differences were found for M. adenantheroides in all treatments. Benomyl and benomyl plus phosphorus treatments reduced AM colonization in all the species under study. Benomyl significantly reduced the number of N₂-fixing root nodules, while the phosphorus treatment generally stimulated nodulation. The species M. lacerata, M. luisana, M. polyantha and M. texana var. filipes had a high mycorrhizal dependency index indicating that plant growth was strongly increased by arbuscular mycorrhiza activity. Our results indicate that the response of all Mimosa species to mycorrhization was highly variable. To our knowledge, this is the first report about the effect of AM fungi and phosphorus on Mimosa species, which may be useful in biodiversity and soil conservation programs.     

A revision of the Megachile subgenus Litomegachile Mitchell with an illustrated key and description of a new species (Hymenoptera,Megachilidae, Megachilini)

The species of Megachile subgenus Litomegachile are revised with a review of the species morphology, biology, and plant associations. A new species, Megachile pankus, is described and illustrated. Megachile mendica snowi Mitchell is elevated to species. Megachile var. nupta Cresson and Megachile texana var. cleomis Cockerell are synonymized with Megachile brevis and Megachile texana, respectively. An illustrated key for Litomegachile is also provided.     

Biosystematic study of Berlandiera (Compositae)

Berlandiera is revised to includeB. subacaulis, B. pumila, B. texana, andB. lyrata with its varietieslyrata andmacrophylla. All species may be induced to interbreed readily, producing F₁ progeny which are vigorous but with reduced fertility. Sympatric species produce natural hybrids which are proposed here asB. Xhumilis (=B. pumila XB. subacaulis) andB. Xbetonicifolia (=B. pumila XB. texana). All taxa investigated hadn = 15 chromosomes, including new counts forB. subacaulis and all six F₁ hybrids.     

Methyl 4-methylpyrrole-2-carboxylate: a volatile trail pheromone from the leaf-cutting ant, tatta cephalotes

Methyl 4-methylpyrrole-2-carboxylate, a volatile trail pheromone previously identified from Atta texana, has been isolated and identified from the ant species, Atta cephalotes. The natural and the synthetic compound produce strong trail-following activity in a laboratory colony of A. cephalotes.     

Faecal proteinases of the fungus-growing ant, Atta texana: Their fungal origin and ecological significance

The fluid contained within the mycelium of the fungus cultured by the attine ant, Atta texana, contains three proteolytic enzymes. One enzyme is a DFP-sensitive alkaline proteinase; the other two are metal-chelator-sensitive neutral proteinases. These three enzymes are indentical by all criteria examined to the three proteinases previously isolated from the faecal fluid of A. texana. It is concluded that the faecal enzymes of the fungus-growing ants are derived from the mycelial fluid upon which they feed. The basis for the symbiosis between the attine ants and the fungi which they cultivate in their nests is reinterpreted in the context of this finding.     

Guaianolide-type sesquiterpene lactones of Montanoa tomentosa subsp. xanthiifolia and M. tomentosa subsp. rosei and the molecular structures of two pumilin analogs

Montanoa tomentosa subsp. xanthiifolia and M. tomentosa subsp. rosei produce guaianolides which are very similar to those previously reported from Berlandiera pumila, B. texana and B. lyatra. The molecular structures of 3α-epoxypumilin and 8-acetyl-9-desacylpumilin-9-methacrylate were determined by single crystal X-ray diffraction.     

Microgeographic allozyme differentiation in the hybrid zone ofMytilus galloprovincialis Lmk. andM. edulis L. on the continental European coast

The EuropeanMytilus galloprovincialis Lmk. andM. edulis L. coexist and hybridize in different proportions in extended areas of the British and Atlantic French coasts.M. galloprovincialis typical allozymes seem to predominate in wave exposed areas, at high levels of attachment and in larger mussels in the British hybrid zone. Mussel samples from exposed and sheltered areas, 200 m apart, and from high and low levels of attachment were collected from a location of the French hybrid zone in 1988–92. PureM. galloprovincialis andM. edulis populations were also taken as controls. Diagnostic enzyme loci for bothMytilus (EST-D ^*, LAP-1^*, MPI^*, ODH^*) andAP-1 ^*, LAP-2^* andPGM ^* loci were studied. The frequencies of theM. galloprovincialis typical alleles were significantly greater in exposed populations than in sheltered samples (e.g. 0.729 to 0.803 vs 0.192 to 0.581 forEST-D ^*90), and at high level of attachment than at low level for the sheltered area (e.g. 0.581 vs 0.192 forEST-D ^*90). PutativeM. galloprovincialis was more abundant on the exposed coast (0.591 and 0.702) than on the sheltered shore, where it predominated at the high shore but not at the low shore location (0.371 vs 0.045). Significantly positive correlations between shell length and typicalM. galloprovincialis compound allele frequencies were found only for populations from exposed areas. Relationships between theMytilus genetic differentiation and ecological factors are discussed.     

A new point of view on the taxonomy ofPottia starckeana agg. (Musci,Pottiaceae)

A new taxonomic treatment is proposed for thePottia starckeana species complex. The peristome development is not considered to be a useful feature to separate the taxa. On the basis of spore morphology only two species are accepted:P. starckeana, with spores wavy in outline, andP. davalliana, with variously-shaped and developed processes on the spores.Pottia starckeana var.brachyoda is reduced to synonymy withP. starckeana; P. conica andP. commutata are treated as synonyms ofP. davalliana. The speciesP. mutica, P. affinis, P. salina, P. microphylla, P. texana, andP. arizonica (included var.mucronulata) are considered taxa of doubtful affinity, as they have spore features intermediate between the two spore types established for the group. The identity ofP. appertii andP. recurvifolia has not been elucidated because the type material has been destroyed.     

Ploidy variation in the group ofMyosotis palustris andM. laxa in the Czech Republic and Slovakia

In 74 natural populations of theMyosotis palustris andM. laxa groups from former Czechoslovakia three euploid and one aneuploid cytotypes were found that belong to the following species:M. nemorosa Besser, 2n=22,M. palustris (L.)Nath. em.Reichenb. inSturm, 2n=66,M. laxiflora Reichenb., 2n=66,M. radicans Opiz, 2n=66(64),M. brevisetacea (Schuster) Holub, 2n=66(64), andM. caespitosa C.F. Schultz, 2n=88. With the exception ofM. nemorosa, the chromosome numbers are published for the first time for the Czech Republic. The chromsome numbers, 2n=66, 2n=64 are found inM. brevisetacea, are new for the literature. The correlation between pollen size and ploidy level has been studied as well, and statistically significant differences were found between cytotypes belonging to different ploidy levels.     

Redescriptions and reestablishments of some species belonging to the genus Prionospio (Polychaeta,Spionidae) and descriptions of three new species

Available type material of Prionospio heterobranchia Moore, 1907, P. (Prionospio) texana Hartman, 1951, P. spongicola Wesenberg-Lund, 1958 and P. (P.) newportensis Reish, 1959, as well as newly collected material from the Southern Gulf of Mexico and Chetumal Bay in the Caribbean Sea, was examined. Several important differences were found between P. heterobranchia, P. (Prionospio) texana, P. spongicola and P. (P.) newportensis, and as a result, these three species are removed from synonymy with P. heterobranchia Moore, 1907, and redescribed and reinstated as valid species. In addition, three new species were identified and described: P. caribensis sp. nov., P. rosariae sp. nov. and P. jamaicensis sp. nov. A key to all species of Prionospio with five pairs of branchiae is provided.     

New records of Peruvian Mikania (Compositae)

Mikania macrostipulata sp. nov. is described, illustrated, and discussed.Mikania dioscoreoides, M. sprucei, andM. trifolia are reported new to Peru. The heterogeneity of the type material ofM. stereodes is also discussed.     

The subdivisions of Magnistipula Engl. (Chrysobalanaceae)

A conspectus of the subgenera and sections ofMagnistipula is provided. Of the two subgenera occurring on the African mainland, subgenusMagnistipula is divided into the sectionsMagnistipula,Animalculum andPeregrinator, whereas subgen.Pellegriniella is monotypic. A Malagasy subgenus,Tolmiella, is new; its two species,M. cerebriformis andM. tamenaka, are transferred fromHirtella.     

Malaxis chica,a new species of Orchidaceae from Nuevo León,Mexico

A new species from northern Mexico,Malaxis chica, is described and illustrated. It is distinguished by its small, unifoliate habit, subumbellate inflorescences, and sagittate lip with long basal lobes.Malaxis chica is compared to three species—M. corymbosa, M. salazarii, andM. rosei—with which it shows some morphological similarity.     

Taxonomic studies in the Miconieae (Melastomataceae). VI. Miconia santanana,a new species from Hispaniola

Miconia santanana, which occurs in broad-leaved forests along streams of pineland habitats in the Cordillera Central of the Dominican Republic, is described and illustrated. It is compared withM. ferruginea andM. adenocalyx, two presumed close relatives withinMiconia sect.Chaenopleura. Eco-geographic characterizations and a key are presented for these three species.