Phylogenetics and biogeography of eastern Asian-North American disjunct genus Pachysandra （Buxaceae） inferred from nucleotide sequences

Pachysandra is an eastern Asian-North American disjtunct genus with three species, two in eastern Asia （Pachysandra axillaris and Pachysandra terminalis） and one in eastern North America （Pachysandra procurnbens）. Although morphological and cytological studies suggest a close affinity of Pprocumbens with P axillaris, molecular data from nuclear and chloroplast DNA regions have provided conflicting signals. In this study, we tested previous phylogenetic hypotheses using sequences of nuclear ribosomal DNA internal transcribed spacers and chloroplast ndhF gene from multiple individuals of each of the three species. We also estimated the time of divergence between eastem Asia and eastern North America. Our results support the morphological and cytological conclusion that P procumbens is more closely related to P axillaris than to P terminalis. The estimated time of divergence of P axillaris and P procumbens was 14.6±5.5 mya, consistent with estimates from many other eastern Asian-North American disjunct genera. The migration of Pachysandra populations from eastern Asia to North America might have occurred by way of the North Atlantic land bridge.     

Triterpenes and sterols of Buxus sempervirens and local variations in their levels

The leaves of Buxus sempervirens L. contain sitosterol, stigmasterol, cycloartenol, lupeol, germanicol and β-amyrin in the free state. All of these compounds, except stigmasterol, were also found in the esters fraction, as were obtusifoliol, 24-methylenelophenol, and 24-ethylidenelophenol, The triterpene diois betulin and moradiol were isolated, the latter for the first time from a plant source. In nineteen Buxus samples from England, Wales and Scotland, the sterol compositions were quite similar while those of the triterpene monols varied considerably.     

Isolation and structure of buxaminol-G,an alkaloid from Buxus papilosa

A new alkaloid, buxaminol-G, has been isolated from the alcoholic extract of the leaves of Buxus papilosa, and its structure assigned on the basis of spectroscopic studies.     

Three new alkaloids from Buxus papillosa

Three new steroidal alkaloids have been obtained from Buxus papillosa Schneider. These are (?)-cyclobuxupaline-C (IV)(+)-cyclopapilosine-D (VII) and (+)-buxamine-C (IX). A known alkaloid also present is desoxy-16-buxidienine (X).     

Cholinesterase inhibitory pregnane-type steroidal alkaloids from Sarcococca hookeriana

The bioassay-guided phytochemical investigation on Sarcococca hookeriana have resulted in the isolation of four new pregnane-type steriodal alkaloids: hookerianamide-D [(2'E,20S)-20-(N,N-formyl(methyl)amino)-3beta-(3',4'-dimethyl-2'-pentenamido)-5alpha-pregnane] (1), hookerianamide-E [(2'E,20S)-20-(N,N-dimethylamino)-3beta-(senecioylamino)-5alpha-pregn-14-en-2beta-O-acetate] (2), hookerianamide-F [(2'E,20S)-20-(N-methylamino)-3beta-(tigloylamino)-5alpha-pregn-2,14-dien-4-one] (3), and hookerianamide-G [(20S)-20-(N,N-dimethylamino)-3beta-(N-methylbenzamido)-5alpha-pregn-4beta-O-acetate] (4), along with five known alkaloids 5-9. Their structures were determined by spectroscopic analysis. These steroidal alkaloids and chemically derived derivatives of compound 5 have displayed varying degree of inhibitory activities against acetylcholinesterase and butyrylcholinesterase enzymes in a concentration-dependent fashion, with the IC(50) values ranging from 1.5 to 148.2 and 0.6 to 100.2 microM, respectively.     

Early Cretaceous floral structures and in situ tricolpate‐striate pollen: New early eudicots from Portugal

Five new taxa with affinities to extant lineages that diverged at an early stage from the main line of eudicot evolution are established from the Early Cretaceous (late Aptian or early Albian) Vale de Agua locality, Portugal. Staminate flowers of Lusistemon striatus and pistillate flowers of Lusicarpus planatus are unisexual without rudiments of the opposite gender. They are linked by the association of an unusual pollen type found in situ in the stamens and adhering to the stigmatic surface. The staminate flower, Lusistemon striatus, is composed of six stamens subtended by small perianth parts. The arrangement of the stamens is difficult to ascertain, but their variable sizes suggests a spiral arrangement. Pollen found in situ is tricolpate and striate with densely‐spaced, sparsely diverging and anastomosing muri that are aligned more or less parallel to the polar axis. The muri have a conspicuous supratectal ornamentation of fine transverse ridges. The granular infratectal layer forms an indistinct internal reticulum. The foot layer is thin. Pollen is closely similar to dispersed grains from the Aptian of Egypt described as STRIOTRI‐SEGMUR. It also resembles pollen of the dispersed pollen genus Rutihesperipites, as well as some dispersed pollen assigned to Striatopollis. Pistillate flowers of Lusicarpus planatus consist of a bicarpellate, syncarpous gynoecium borne on a short stalk. The styles are bent outwards and expose the double‐crested stigmatic regions on their ventral sides. The only organ preserved besides the gynoecium is a lateral scale‐like organ at the base of the stalk. Pollen of the same type found in Lusistemon striatus occurs on the stigmatic surface of the carpels. Comparisons with extant taxa demonstrate that Lusistemon and Lusicarpus share many characters with early diverging groups of eudicots, in particular Buxaceae. In addition to the Lusistemon‐Lusicarpus flowers, the Vale de Agua samples also contain three other pistillate reproductive structures that may be related to early diverging lineages of eudicots. Silucarpus camptostylus has a bicarpellate and syncarpous gynoecium with two styles; Valecarpus petiolatus and Aguacarpus hirsutus have tricarpellate gynoecia that are distinguished from each other in the shape and extension of the stigma as well as other details.     

The saga of the spurges: a review of classification and relationships in the Euphorbiales

The saga of the spurges: a review of classification and relationships in the Euphorbiales. The order Euphorbiales, defined by Lindley in 1836, has undergone many vicissitudes to the present day. Over 30 families have been referred to the Euphorbiales by various authors, but most of them no longer appear closely related to the Euphorbiaceae. Several families commonly referred to Euphorbiales (or Tricoccae) in the 19th century now appear better located in other orders: Buxaceae in Hamamelidales (sensu lato), Empetraceae in Ericales, and Callitrichaceae in Lamiales. Several putatively related families, including the Aextoxicaceae, Stackhousiaceae, and Dichapetalaceae, appear to be of Celastralean affinity. The Simmondsiaceae, a problematical family once referred to the Buxaceae, have been included in the Euphorbiales in recent classifications, but the evidence for this is still inconclusive. Thymelaceaceae show a number of similarities to Euphorbiaceae, but share a greater number of distinctive characters with Malvales. The Euphorbiales show affinities to both the Malvales and Geraniales {sensu lato), and separation of these three orders between two major dicotyledon subclasses (Dilleniidae and Rosidae) appears questionable. The evidence does not support recognizing segregate families from the Euphorbiaceae such as the Bischofiaceae, Picrodendraceae and Stilaginaceae; the Euphorbiales are therefore best construed as containing a single major family, the Euphorbiaceae, as suggested by Hutchinson; the small family Pandaceae is also included in the Euphorbiales but may not be separable from the Euphorbiaceae. The recent classifications of Airy Shaw and Webster agree in many respects, and areas of disagreement indicate the need for additional data gathering and analysis.     

Segregate families from the Euphorbiaceae

Segregate families from the Euphorbiaceae. Several families have been segregated from the Euphorbiaceae. Some of these are of long-standing, and are now generally accepted. Others are more recent, and somewhat controversial. Five such have recently been recognized at Kew, and are discussed here, as are two others which have not been so recognized.