Emergence, trapping, and seasonal abundance of adult Cerambycidae (Coleoptera) associated with Cupressaceae in Connecticut

Emergence, attraction to traps, and seasonal abundance of cerambycids (Coleoptera) whose larvae injure Cupressaceae were studied under natural conditions in southern Connecticut between 1999 and 2005. Adults of the Asian cerambycid Callidiellum rufipenne (Motschulsky) emerged from trunk sections of Thuja occidentalis L. between late March and mid-May. In contrast, the native Atimia confusa confusa (Say) emerged from trunk sections of Juniperus virginiana L. between late August and mid-October. Emerged adults of both cerambycids had a 1:1 sex ratio, and the emergence of Callidiellum rufipenne showed protandry. In a comparison of four trapping methods, sticky bands stapled to trap logs and dead trees of J. virginiana had the highest density of adults of A. confusa confusa and Callidiellum rufipenne. Based on adults trapped on sticky bands on trap logs, dead trees, or girdled trees of J. virginiana or T. occidentalis at different locations, Callidiellum rufipenne was active on hosts for 5-8 wk between April and June; Semanotus ligneus ligneus (Say) for 4 wk in April; Callidium frigidum Casey for 5 wk between early May and early June; and A. confusa confusa for approximately 12 wk between April and early July and again for 2-5 wk between September and late October. Catches of A. confusa confusa were significantly female-biased. Number of beetles captured usually was not correlated with the size of the sticky band on trap logs, cut trees, or girdled trees. This is the first quantitative study on emergence, trapping, and seasonal abundance of cerambycids associated with Cupressaceae in northeastern North America.     

Survival and development of Lymantria monacha (Lepidoptera: Lymantriidae) on North American and introduced Eurasian tree species

Lymantria monacha (L.) (Lepidoptera: Lymantriidae), the nun moth, is a Eurasian pest of conifers that has potential for accidental introduction into North America. To project the potential host range of this insect if introduced into North America, survival and development of L. monacha on 26 North American and eight introduced Eurasian tree species were examined. Seven conifer species (Abies concolor, Picea abies, P. glauca, P. pungens, Pinus sylvestris with male cones, P. menziesii variety glance, and Tsuga canadensis) and six broadleaf species (Betula populifolia, Malus x domestica, Prunus serotiaa, Quercus lobata, Q. rubra, and Q. velutina) were suitable for L. monacha survival and development. Eleven of the host species tested were rated as intermediate in suitability, four conifer species (Larix occidentalis, P. nigra, P. ponderosa, P. strobus, and Pseudotsuga menziesii variety menziesii) and six broadleaf species (Carpinus caroliniana, Carya ovata, Fagus grandifolia, Populus grandidentata, Q. alba, and Tilia cordata) and the remaining 10 species tested were rated as poor (Acer rubrum, A. platanoidies, A. saccharum, F. americana, Juniperus virginiana, Larix kaempferi, Liriodendron tulipfera, Morus alba, P. taeda, and P. deltoides). The phenological state of the trees had a major impact on establishment, survival, and development of L. monacha on many of the tree species tested. Several of the deciduous tree species that are suitable for L. monacha also are suitable for L. dispar (L.) and L. mathura Moore. Establishment of L. monacha in North America would be catastrophic because of the large number of economically important tree species on which it can survive and develop, and the ability of mated females to fly and colonize new areas.     

Late Embryogeny of Pinus bungeana

Except for Pseudolarix, which is endemic to China, the late embryogeny of ten genera of Pinaceae has been reported before in the diffferent degree. Among them the mature embryos of Keteleeria evelyniana are different from those of the others in having well-developed cotyledons and a very short hypocotyl. As far as information we have is concerned there are three types in structure of the mature embryos of Pinaceae. The first type occurs in Keteleeria and Cedrus, which have very well-developed cotyledons; the second one appears in Picea and Larix, in which the hypocotyl and the root cap are equal in length; the third one, to which Pinus bungeana belongs, includes all the other genera of Pinaceae. The last type is of a prominent hypocotyl in the mature embryos. It is interesting to note that the mature embryos of Torreya grandis and Keteleeria evelyniana are very similar in having specially developed cotyledons, while the proportions of the various tissues in the mature embryo in Fokienia of Cupressaceae as well as Taxus and Amentotaxus of Taxaceae are similar to those of Pinus bungeana. The pith and secretory cells are usually present in the mature embryos of Pinaceae. Although no pith is present in those of Metasequoia and Taiwania of Taxodiaceae, the secretory cells generally occur in their embryos in Fokienia of Cupressaceae and Taxus and Pseudotaxus of Taxaceae, neither pith nor secretory cells are present in their hypocotyl. From above, the structures of mature embryos among Pinaceae, Taxodiaceae and Cupressaceae are different from one another to some degree. The most outstanding feature of the matur embryos in Pinus bungeana is that the shoot apex is very well developed, with a high H/D ratio, about 0.83 on an average, even up to 0.96 in some case. Above-mentioned H/D ratio of Pinus bungeana is rare in the mature embryos of conifers. Gifford (1943) reports that the average H/D ratio of shoot apex of Ephedra altissima is from 0.44 to 0.68, while in 5-year-old branch apex of Pinus ponderosa, the average ratio is about 0.25, and that in l5-year-old branch apex is about 0.35. For the apex of the dormant short shoots of Pinus densiflora the average ratio is about 0.35, but that of shoot apex is about 0.52 when new buds have just formed. According to the present data about shoot apices of both branches and mature embryos, the average ratio of shoot apex of mature embryos in Pinus bungeana is the largest one. From the present investigation the shoot apex of mature embryos of Pinus bungeana exhibits four distinct tissue zones, i.e. the apical initials, the central mother cell zone, the peripheral tissue zone and the rib meristem. It is worthy of note that the shoot apex of Pinus strobus may be divided into five zones, including transition zone between central mother cells and rib meristem (Owston, 1968). Four zones are recognized in the shoot apex of Pinus lambertiana and P. ponderosa, without transition one (Sacher, 1954). From cytological zonation, the shoot apex of mature embryos in Pinus bungeana is rather similar to that of Pinuslambertiana and P. ponderosa.     

光学显微镜下松柏类和菊科花粉的分类、鉴定要点及生态意义

本文对地层中广泛分布的松柏类和菊科花粉进行初步分类,讨论各类型(属)的鉴定特征及生态意义.以气囊的有无、外壁结构和纹饰、气囊的形态和纹饰、本体与气囊过渡点的特征、帽与帽缘纹理等为鉴定要点,对杉型、柏科型、刺柏型、红豆杉型、落叶松属、铁杉属、罗汉松属、云杉属、雪松属、冷杉属、油杉属和松属(双束松型和单束松型)13个类型的松柏类植物花粉逐步分类.通过总结前人研究和统计分析,讨论落叶松属、铁杉属、罗汉松属、云杉属、雪松属、冷杉属、油杉属和松属,特别是双束松型和单束松型花粉的生态环境指代意义.依据花粉的大小、外壁表面纹饰、外壁光切面中基柱层的结构和发育程度,初步拟将菊科花粉划分为6个类型,即菊苣-蒲公英型、紫菀型、春黄菊型、风毛菊型、蓝刺头型和蒿属,并通过对6个花粉类型植物母体生态环境的归纳总结和统计分析,讨论它们的生态环境指代意义.     

广西裸子植物

广西本土生长的裸子植物共43种,包含苏铁科3种,三尖杉科4种,红豆杉科4种,罗汉松科6种,松科17种,杉科1种,柏科3种,和买麻藤科5种。虽然它们在本区分布较广,但其种类多集中于北部和中部属酸性土且气候较凉的山脉上。 油杉有数种生长在石灰岩石山上,它们比低地的松树之外的裸子植物较为耐旱。少数种类稀少且分布局限,少数为特有。 经作者研究,广西裸子植物的学名有些需要修改:Cephalotaxus hainanensis和C.griffithii应归并于C.mannii;Podocarpus imbricatus需改为DacrycarPus imbricatus,Podocarpusfteuryi或Deeusocarpus fleuryi改为Nageia fteuryi,Podocarpus nagi或Decuso-corpus nagi改为Nageia nagi,过去误定为Podocarpus brevifolius或P.wangii应改为Podocarpus pilgeri;Kereleeria pubescens应归并于K.davidiana,K.hainanensis归并于K.evelyniana,K.eyelolepis和K.oblonga归并于K.fortunei;Tsuga longibra-cteata改为Nothotsuga longibracteata;Cupressus funebris改为Chamaecyparis fune-bris,不同意把Pinus Kwangtungensis改为p.wangii var.kwangtungensis等。     

Suitability of some southern and western pines as hosts for the pine shoot beetle, Tomicus piniperda (Coleoptera: Scolytidae)

The pine shoot beetle, Tomicus piniperda (L.), is an exotic pest that has become established in North America. Discovered in Ohio in 1992, it has since been found in at least 13 states and parts of Canada. The beetle can cause significant growth loss in pines, and it represents a potential threat to trees in areas where it has not yet become established. To evaluate this threat to native pines, field and laboratory tests were conducted on several common and important southern and western species to determine whether they are acceptable hosts for T. piniperda. Comparisons with Pinus sylvestris L., Scots pine, a preferred natural host for the beetle, were made where possible. Measurements of beetle attack success on southern pine billets showed that Pinus taeda L., Pinus echinata Miller, Pinus elliottii var. elliottii Engelmann, Pinus palustris Miller, and Pinus virginiana Miller (loblolly, shortleaf, slash, longleaf, and Virginia pine, respectively) and two western pines, Pinus ponderosa Lawson and Pinus contorta Douglas (ponderosa and lodgepole pine, respectively), were acceptable for breeding material, but brood production was highly variable. Among the southern pines, P. taeda and P. echinata were susceptible to shoot feeding by T. piniperda, whereas P. elliottii was highly resistant and P. palustris seemed to be virtually immune. Shoot feeding tests on the western pines were conducted only in the laboratory, but there was moderate-to-good survival of adults feeding on both species. It seems that if T. piniperda is introduced into the south and west it will likely establish and may cause some damage to native pines. P. taeda may be affected more than other southern pines because it is the most abundant species, it is readily attacked for brood production, which can result in moderately large broods, and the beetle survives well during maturation feeding on P. taeda shoots.     

Interspecific variation in sapling mortality in relation to growth and soil moisture

To examine the causes of landscape variation in forest community composition, we have quantified sapling mortality as a function of growth and soil moisture for seven dominant species in transition oak-northern hardwood forests of the northeastern USA. We located saplings in sites that encompassed a wide range of variation in soil moisture and light availability. In mesic conditions, the probability of mortality decays rapidly with increasing growth among shade tolerant species and more gradually among shade intolerant species: the rank order of survivorship at low growth rates is Tsuga canadensis > Fagus grandifolia > Acer saccharum > Fraxinus americana > Acer rubrum > Quercus rubra > Pinus strobus . The relationship between probability of mortality and growth does not vary with soil moisture among species insensitive to drought: Tsuga canadensis , Quercus rubra, and Pinus strobus . However, probability of mortality increases substantially with decreasing soil water availability for the other four species. Acer saccharum and Fagus grandifolia have high mortality rates under xeric conditions even when their growth is not suppressed. Acer rubrum and Fraxinus americana exhibited a steady but more gradual increase in the probability of mortality with decreasing soil moisture. Among the five deciduous hardwood species we examined there is a weak inverse relationship between the ability to survive growth suppression, a measure of shade tolerance, and the ability to survive in xeric conditions, a measure of drought tolerance. Tsuga canadensis , however, is tolerant of growth suppression and exhibits high survivorship in xeric conditions, while Pinus strobus is intolerant of growth suppression but insensitive to soil moisture. Species differences in water-dependent mortality are consistent with the species distributions across landscape gradients of soil water availability.     

Taxonomy of gymnospermae: multivariate analyses of leaf fatty acid composition

The fatty acid composition of photosynthetic tissues from 137 species of gymnosperms belonging to 14 families was determined by gas chromatography. Statistical analysis clearly discriminated four groups. Ginkgoaceae, Cycadaceae, Stangeriaceae, Zamiaceae, Sciadopityaceae, Podocarpaceae, Cephalotaxaceae, Taxaceae, Ephedraceae and Welwitschiaceae are in the first group, while Cupressaceae and Araucariaceae are mainly in the second one. The third and the fourth groups composed of Pinaceae species are characterized by the genera Larix, and Abies and Cedrus, respectively. Principal component and discriminant analyses and divisive hierarchical clustering analysis of the 43 Pinaceae species were also performed. A clear-cut separation of the genera Abies, Larix, and Cedrus from the other Pinaceae was evidenced. In addition, a mass analysis of the two main chloroplastic lipids from 14 gymnosperms was performed. The results point to a great originality in gymnosperms since in several species and contrary to the angiosperms, the amount of digalactosyldiacylglycerol exceeds that of monogalactosyldiacylglycerol.     

Molecular phylogeny and evolution of host-plant use in conifer seed chalcids in the genus Megastigmus (Hymenoptera: Torymidae)

Abstract. Phylogenetic relationships amongst Megastigmus species (Chalcidoidea: Torymidae) associated with conifer seeds were inferred from DNA sequence data. Twenty‐nine species of seed chalcids were analysed using two different genes, cytochrome b (mitochondrial DNA) and the D2 domain of the 28S ribosomal DNA. Maximum‐parsimony and maximum‐likelihood analyses showed that taxa formed two monophyletic groups, one clade comprising all species associated with Cupressaceae and Taxodiaceae hosts with the exception of Chamaecyparis, and the other clade composed of species associated with Pinaceae. Species infesting Cupressaceae and Taxodiaceae seemed to be specialized to particular host genera or even to be species specific, which was consistent with a taxonomic radiation following initial host adaptation. By contrast, Megastigmus species associated with Pinaceae appeared capable of shifting onto different congeneric species or even onto a new host genus, with their evolution apparently less constrained by plant association. We hypothesized that the Megastigmus group associated with Pinaceae may have a much higher invasive potential than that related to Cupressaceae. The study also confirmed the presence of invasive Nearctic species in the Palaearctic, and demonstrated the existence of a cryptic species complex.     

Mapped DNA probes from loblolly pine can be used for restriction fragment length polymorphism mapping in other conifers

A high-density genetic map based on restriction fragment length polymorphisms (RFLPs) is being constructed for loblolly pine (Pinus taeda L.). Consequently, a large number of DNA probes from loblolly pine are potentially available for use in other species. We have used some of these DNA probes to detect RFLPs in 12 conifers and an angiosperm. Thirty complementary DNA and two genomic DNA probes from loblolly pine were hybridized to Southern blots containing DNA from five species of Pinus (P. elliottii, P. lambertiana, P. radiata, P. sylvestris, and P. taeda), one species from each of four other genera of Pinaceae (Abies concolor, Larix laricina, Picea abies, and Pseudotsuga menziesii), one species from each of three other families of Coniferales [Sequoia sempervirens (Taxodiaceae), Torreya californica (Taxaceae) and Calocedrus decurrens (Cupressaceae)], and to one angiosperm species (Populus nigra). Results showed that mapped DNA probes from lobolly pine will cross-hybridize to genomic DNA of other species of Pinus and some other genera of the Pinaceae. Only a small proportion of the probes hybridized to genomic DNA from three other families of the Coniferales and the one angiosperm examined. This study demonstrates that mapped DNA probes from loblolly pine can be used to construct RFLP maps for related species, thus enabling the opportunity for comparative genome mapping in conifers.     

Adventitious root production and plastic resource allocation to biomass determine burial tolerance in woody plants from central Canadian coastal dunes

BACKGROUND AND AIMS: Burial is a recurrent stress imposed upon plants of coastal dunes. Woody plants are buried on open coastal dunes and in forested areas behind active blowouts; however, little is known about the burial responses and adaptive traits of these species. The objectives of this study were: (a) to determine the growth and morphological responses to burial in sand of seven woody plant species native to central Canadian coastal dunes; and (b) to identify traits that determine burial tolerance in these species. METHODS: Field experiments were conducted to determine the responses of each species to burial. Saplings were exposed to burial treatments of 0, 10, 25, 50 and 75 % of their height. Burial responses were evaluated based on regressions of total biomass, height, adventitious root production and percentage allocation to shoot, root and adventitious root biomass on percentage burial. KEY RESULTS: Pinus strobus and Picea glauca lacked burial tolerance. In response to the burial gradient, these species showed a strong linear decline in total biomass, minimal adventitious root production that peaked at moderate levels (25-50 % burial) and no change in allocation to shoots vs. roots. The tolerant species Juniperus virginiana, Thuja occidentalis and Picea mariana showed a quadratic response to burial, with little change in biomass up to 50 % burial, but a large decline at 75 %. These species produced abundant adventitious roots up to 50 % burial, but did not alter allocation patterns over the range of burial levels. Populus balsamifera and Salix cordata were stimulated by burial. These species showed linear increases in biomass with increasing burial, produced copious adventitious roots across the gradient and showed a clear shift in allocation to vertical shoot growth and adventitious root production at the expense of the original roots under high burial conditions. CONCLUSIONS: Adventitious root production and plastic resource allocation to biomass are adaptive traits of coastal dune woody plants in central Canada, and provide a basis for assessing burial tolerance in woody plants on coastal dunes throughout the world.     

Speciation by host-switching in pinyon Cinara (Insecta: Hemiptera: Aphididae)

Parasite-host cospeciation has received much attention as an important mechanism in the diversification of phytophagous insects. However, studies have shown that for certain taxa, it is not host fidelity but host-switching that plays the critical role in speciation. Cinara are aphids (Insecta: Hemiptera: Aphididae: Lachninae) that feed exclusively on the woody parts of conifers of the Cupressaceae and Pinaceae. They are unusual aphids because most Pinaceae play host to several species of Cinara. The aphids show relatively strong host fidelity, and as a consequence historically have been treated based on the taxonomy of their hosts. The historical paradigm of aphid evolution implies that Cinara species have radiated to different parts of the same host species and/or speciated with their host. Using mitochondrial cytochrome oxidase 1 and nuclear elongation factor 1-alpha DNA sequences, we performed molecular phylogenetic analysis of Cinara species, concentrating on those associated with pinyon pines in the southwestern USA. We determined that switching hosts has played a key role in the speciation of the genus, reflected in the polyphyly of pinyon-feeding Cinara. Furthermore, species sharing a common feeding site on different hosts were more closely related to each other than to those sharing the same host but at different feeding sites, suggesting that feeding site fidelity plays a more important role in speciation than does host fidelity in general. This study also elucidated the primary taxonomy of various species: it suggested that Cinara rustica Hottes is a junior synonym of C. edulis (Wilson) and that C. wahtolca Hottes represents two species on the two different pinyon pine species, Pinus edulis Englem. and P. monophylla Torr. & Frem.     

Selection for commercial forestry determines global patterns of alien conifer invasions

Question Are the patterns of alien conifer (Pinaceae, Cupressaceae) invasions different between continents, and how is invasion success influenced by commercial forestry practices? Location Temperate and subtropical countries and regions (n = 60) from five continents spanning both hemispheres. Methods We used generalized linear mixed models to test how continent identity, region area and use in commercial forestry affect probabilities of Pinaceae and Cupressaceae species to escape following introduction and cumulative logit regression models to assess how these predictors affect the likelihood that a species becomes naturalized or invasive. Results Sixty Pinaceae of a global total of 232 and 26 Cupressaceae of a total of 142 species have escaped from cultivation across the study regions examined. Average numbers of both alien Pinaceae and Cupressaceae species per region were highest in Oceania, followed by Africa. Moreover, the probability of alien Cupressaceae and Pinaceae becoming naturalized or invasive was particularly high in these two continents. For both families, species used in commercial forestry have a significantly higher probability of escape than those which are only introduced for ornamental or other purposes. In the case of Pinaceae, forestry species also become naturalized or invasive more frequently than non‐forestry species, while no such effect was detectable for Cupressaceae. Conclusions We found that non‐native conifers are more likely to escape from cultivation, naturalize and turn into invasive weeds on the continents of the Southern Hemisphere. In addition to this biogeographic signal, introduction effort strongly determines the behaviour of introduced Pinaceae, and less so, Cupressaceae. A clear conflict exists between the economic benefits of conifer forestry and the risks to the environment from invasions. Future expansion of commercial forestry should address spatial planning to ecosystems vulnerable to invasion and adopt comprehensive risk assessment procedures.     

Parenchyma cell respiration and survival in secondary xylem: does metabolic activity decline with cell age?

Sapwood respiration often declines towards the sapwood/heartwood boundary, but it is not known if parenchyma metabolic activity declines with cell age. We measured sapwood respiration in five temperate species (sapwood age range of 5-64 years) and expressed respiration on a live cell basis by quantifying living parenchyma. We found no effect of parenchyma age on respiration in two conifers (Pinus strobus, Tsuga canadensis), both of which had significant amounts of dead parenchyma in the sapwood. In angiosperms (Acer rubrum, Fraxinus americana, Quercus rubra), both bulk tissue and live cell respiration were reduced by about one-half in the oldest relative to the youngest sapwood, and all sapwood parenchyma remained alive. Conifers and angiosperms had similar bulk tissue respiration despite a smaller proportion of parenchyma in conifers (5% versus 15-25% in angiosperms), such that conifer parenchyma respired at rates about three times those of angiosperms. The fact that 5-year-old parenchyma cells respired at the same rate as 25-year-old cells in conifers suggests that there is no inherent or intrinsic decline in respiration as a result of cellular ageing. In contrast, it is not known whether differences observed in cellular respiration rates of angiosperms are a function of age per se, or whether active regulation of metabolic rate or positional effects (e.g. proximity to resources and/or hormones) could be the cause of reduced respiration in older sapwood.     

A Dendroctonus bark engraving (Coleoptera: Scolytidae) from a middle Eocene Larix (Coniferales: Pinaceae): early or delayed colonization?

An engraving made by a scolytid bark beetle, assigned to the genus Dendroctonus of the tribe Tomicini, has been identified on a mummified, middle Eocene (45 Ma) specimen of Larix altoborealis wood from the Canadian High Arctic. Larix altoborealis is the earliest known species of Larix, a distinctive lineage of pinaceous conifers that is taxonomically identifiable by the middle Eocene and achieved a broad continental distribution in northern North America and Eurasia during the late Cenozoic. Dendroctonus currently consists of three highly host-specific lineages that have pinaceous hosts: a basal monospecific clade on Pinoideae (Pinus) and two sister clades that consist of a speciose clade associated exclusively with Pinoideae and six species that breed overwhelmingly in Piceoideae (Picea) and Laricoideae (Pseudotsuga and Larix). The middle Eocene engraving in L. altoborealis represents an early member of Dendroctonus that is ancestral to other congeneric species that colonized a short-bracted species of Larix. This fossil occurrence, buttressed by recent data on the phylogeny of Pinaceae subfamilies and Dendroctonus species, indicates that there was phylogenetically congruent colonization by these bark-beetle lineages of a Pinoideae + (Piceoideae + Laricoideae) host-plant sequence. Based on all available evidence, an hypothesis of a geochronologically early invasion during the Early Cretaceous is supported over an alternative view of late Cenozoic cladogenesis by bark beetles onto the Pinaceae. These data also suggest that host-plant chemistry may be an effective species barrier to colonization by some bark-beetle taxa over geologically long time scales.     

The phylogenetic position of taxaceae based on 18S rRNA sequences

The evolutionary position of the yew family, Taxaceae, has been very controversial. Some plant taxonomists strongly advocate excluding Taxaceae from the conifer order and raising its taxonomic status to a new order or even class because of its absence of seed cones, contrary to the case in the majority of conifers. However, other authors believe that the Taxaceae are not fundamentally different from the rest of the conifers except in that they possess the most reduced solitary-ovule cones. To resolve the controversy, we have sequenced the 18S rRNA genes from representative gymnosperms: Taxus mairei (Taxaceae), Podocarpus nakaii (Podocarpaceae), Pinus luchuensis (Pinaceae), and Ginkgo biloba (Ginkgoales). Our phylogenetic analysis of the new sequence data with the published 18S rRNA sequence of Zamia pumila (a cycad) as an outgroup strongly indicates that Taxus, Pinus, and Podocarpus form a monophyletic group with the exclusion of Ginkgo and that Taxus is more closely related to Pinus than to Podocarpus. Therefore, Taxaceae should be classified as a family of Coniferales. Our finding that Taxaceae, Pinaceae, and Podocarpaceae form a clade contradicts both the view that the uniovulate seed of Taxaceae is a primitive character and the view that the Taxaceae are descendants of the Podocarpaceae. Rather, the uniovulate seed of Taxaceae and that of some species of Podocarpus appear to have different origins, probably all reduced from multiovulate cones. Correspondence to: W.-H. Li     

Chemotaxonomic differentiation of conifer families and genera based on the seed oil fatty acid compositions: multivariate analyses

 The fatty acid compositions of seed oils from 34 conifer species, mainly Pinaceae and secondarily Cupressaceae, have been determined by gas-liquid chromatography of the methyl esters. As noted in earlier studies, these oils were characterized by the presence of several Δ5-olefinic acids, i.e., 5,9-18:2, 5,9,12-18:3, 5,9,12,15-18:4, 5,11-20:2, 5,11,14-20:3, and 5,11,14,17-20:4 acids, in addition to the more common saturated, oleic, linoleic and α-linolenic acids. Based on these fatty acid compositions, and on those established in earlier systematic studies (totalling 82 species), we established a chemotaxonomic grouping of the main conifer families, i.e., of the Pinaceae, Taxodiaceae, Cupressaceae, and Taxaceae. This was achieved using multivariate analyses (principal component analysis and discriminant analysis). The fatty acids that discriminate best in this classification are the 5,11,14,17-20:4, 9,12,15-18:3 and 5,9,12-18:3 acids. Moreover, it was possible to differentiate between several genera of the Pinaceae: Pinus (including Tsuga and Pseudotsuga), Abies, Cedrus, and Picea plus Larix, represented quite distinct groups. Other fatty acids such as oleic, linoleic, and 5,9-18:2 acids were also important for this purpose. The fatty acid compositions, and particularly the Δ5-olefinic acid contents of conifer seed oils, may thus be applied to the chemosystematic distinction among conifer families as well as genera of the Pinaceae. Received: 3 January 1997 / Accepted: 17 April 1997     

Sesqui-, di-, and triterpenoids as chemosystematic markers in extant conifers—A review

Chemosystematics is a common tool in systematics and taxonomy of extant plants. Terpenoids have been found to be especially valuable for chemosystematic investigations of conifers. A review of data in the extensive literature revealed some characteristic distribution patterns of sesqui-, di-, and triterpenoids in extant conifer families. The numerous terpenoids can be assigned to approximately 40 sesquiterpenoid, 17 diterpenoid, and only a few triterpenoid structural classes. Some of these terpenoid classes (e.g., cadinanes, humulanes, labdanes, pimaranes) are unspecific and distributed among all conifers. Other structural classes occur in certain clusters of families (e.g., totaranes in Podocarpaceae, Taxodiaceae, and Cupressaceae s.str.) or were restricted to species of only one conifer family (e.g., cuparanes in Cupressaceae s.str.). Cupressaceae s.str. and Taxodiaceae show great similarities in their terpenoid composition (cedranes, thujopsanes) but can be separated by the occurrence of some sesquiterpenoids (cuparanes, widdranes), which were hitherto known only in Cupressaceae s.str. This supports a monophyletic clade of Cupressaceae s.str. within the major Taxodiaceae/Cupressaceae lineage (= Cupressaceae s.l.). Pinaceae differ from the other conifer families because they commonly lack several diterpenoid classes (phenolic abietanes, tetracyclic diterpenoids) and because they contain some distinct sesquiterpenoids (longicyclanes, sativanes), diterpenoids (cembranes), and triterpenoids (serratanes, lanostanes). With the exception of diterpenoid alkaloids (taxanes), Taxaceae contain terpenoids common in the other conifer families. This supports their inclusion as a separate family in the major conifer clade.