TRIGONOBALANUS (FAGACEAE): TAXONOMIC STATUS AND PHYLOGENETIC RELATIONSHIPS

The fagaceous genus Trigonobalanus as recently treated includes 3 species, two in Malaysia and Southeast Asia and a single species in Colombia, South America. Character analysis suggests that the genus as currently circumscribed is paraphyletic, without synapomorphies to unite the three species. Each of the three species is a morphologically distinct relict of a group that probably was ancestral to the modern genera Quercus and Fagus. Each of the three species also has at least one autapomorphy which is unique within Fagaceae. Analysis of cupule morphology in Fagaceae provides an interpretation of evolution in cupules which differs substantially from Forman's interpretation. We interpret trigonobalanoid cupules as indicative of an ancestral type of inflorescence within Fagaceae. This inflorescence type is a dichasial structure in which the outermost axes are cupular valves, but the degree of branching and subsequent number of fruits are variable. Following this model, a strict relationship exists between valve number and fruit number as seen in cupules of Trigonobalanus (valves = fruits + 1). Fossil evidence is consistent with our interpretation of the phylogenetic position of the trigonobalanoids. We propose to segregate the three species of Trigonobalanus as three monotypic genera; two of these require names which we provide here: Formanodendron and Colombobalanus.     

PSEUDOFAGUS IDAHOENSIS,N. GEN. ET SP. (FAGACEAE) FROM THE MIOCENE CLARKIA FLORA OF IDAHO

A new genus and species of Fagaceae are established for compressed leaves and attached fruits which represent one of the dominant taxa in the rich Miocene Clarkia flora of northern Idaho. The leaf and fruit morphology, cuticular and pericarp anatomy, and leaf phytoliths fall within the range of variation of the subfamily Fagoideae. The unique fruit consists of a large, exposed, distinctly keeled, trigonous nut and a diminutive basal cupule. The cupule has an apical frill of free, petiolate, leaflike appendages but lacks other ornamentation, and there is no evidence of a distinct Valvation. As no other genus of the Fagaceae has fruits with this combination of characters, a new genus is established and is referred to the subfamily Fagoideae. The Miocene genus seems most closely related to the extant genus Fagus.     

BIRD-DISPERSAL OF PHYTOLACCA AMERICANA L. AND THE INFLUENCE OF FRUIT REMOVAL ON SUBSEQUENT FRUIT DEVELOPMENT

Characteristics of fruits, seeds, and ripening of Phytolacca americana were studied in New Jersey, USA to assess their importance in the dispersal strategy of this species. Removal by birds was directly related to the percent of ripe fruits available on a raceme. Fruit removal from a raceme resulted in lower fruit pulp and seed weights for fruits developing on the same raceme, but these differences probably do not influence probability for dispersal by birds. We demonstrate that characteristics of the fruit pulp may decrease seed availability for the primary seed predator, Peromyscus leucopus, and increase the time fruits are available for dispersal. We speculate on the significance of the sequential fruiting in Phytolacca and the relationship to availability of dispersal agents and high-lipid fruits. Sequential ripening and protection from predation result in seed dispersal from late August to early December.     

ATTACHED REPRODUCTIVE AND VEGETATIVE REMAINS OF THE EXTINCT AMERICAN-EUROPEAN GENUS CEDRELOSPERMUM (ULMACEAE) FROM THE EARLY TERTIARY OF UTAH AND COLORADO

Fossil twigs with attached foliage, fruits, and flowers from the middle Eocene of the Green River Formation in northeastern Utah and northwestern Colorado and from the early Oligocene Florissant beds of central Colorado provide a firm basis for reconstructing two species of an extinct ulmaceous genus that was widely distributed in the Tertiary of midlatitude western North America and Europe. The fruits are samaras of Cedrelospermum Saporta, a genus previously known only from isolated specimens. The distichously arranged, slender, pinnate-veined leaves vary from serrate with simple teeth to, less commonly, entire-margined. Corresponding isolated leaves in the Green River, Florissant, and other Eocene to Oligocene localities of western North America are now excluded from Zelkova and Myrica, to which they were previously misidentified. The anthers of the staminate flowers contain 3–5 porate pollen with rugulate sculpture. Based upon combined characters of phyllotaxy, and leaf, flower, fruit, and pollen morphology, Cedrelospermum can be referred to the extant subfamily Ulmoideae, and is similar to Phyllostylon, Zelkova, and Hemiptelea. The abundance of Cedrelospermum in lake sediments of volcanic areas, together with its production of numerous small winged fruits, suggest that it was an early successional colonizer of open habitats.     

INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: A MIMOSOID INFLORESCENCE

Six examples of a spicate inflorescence from the Middle Eocene Claiborne Formation in western Tennessee have been investigated. Individual flowers are small, alternately arranged, nearly sessile, and perfect. The style protrudes 2 mm beyond the floral envelope and terminates in a slightly swollen, rounded stigma. Both the style and the stigma are hairy. Ten stamens are exserted and extend 5 mm beyond the floral envelope. Anthers are small, versatile, and dehisce longitudinally. Pollen grains are tricolporate, tectate, and are in permanent tetrahedral tetrads 32 μm in diameter. Comparison of the fossil inflorescences with those of extant families having multiple pollen grain configurations suggests that the fossil inflorescences are most closely allied to the subfamily Mimosoideae of the Leguminosae. These are the first structurally documented remains of the Mimosoideae from the Middle Eocene.     

THE PLATYCARYA PERPLEX AND THE EVOLUTION OF THE JUGLANDACEAE

We report on the leaves, fruits, inflorescences, and pollen of two fossil species in the genus Platycarya. The association of these dispersed organs has been established by their repeated co-occurrence at a large number of localities, and for two of the organs (fruit and pistillate inflorescence, and pollen and staminate inflorescence) by apparent organic attachment of compression fossils. Each of the two species can be distinguished by characteristics of all the known megafossil organs. We also review the fossil record of dispersed platycaryoid fruits and inflorescences, recognizing three additional species of Platycarya and two of Hooleya. Two of the fossil Platycarya species are morphologically very different from the living Platycarya strobilacea Sieb. et Zucc., but they show the diagnostic features of the genus. Hooleya is a generalized member of the Platycaryeae that is probably close to the ancestry of Platycarya. The two Platycarya species known from multiple organs provide a remarkable example of mosaic evolution in which fertile and foliar structures have attained different levels of morphological specialization. The leaves, often considered the most plastic of plant organs, retain several features that are otherwise seen only in the Engelhardieae. These similarities in leaf architecture between the fossil Platycarya species and Engelhardieae are advanced features for the Juglandaceae, and thus indicate a sister-group relationship between the two lines. In contrast to the leaves, the fruits, inflorescences, and pollen of the fossil Platycarya species are almost as specialized as those of the extant P. strobilacea and bear little resemblance to the same structures in other genera of the family. The morphology, taphonomy, sedimentary setting, and geographic and stratigraphic distribution of three of the fossil platycaryoid species suggest that they were wind-dispersed, early successional plants that grew in thickets. This habit is retained by Platycarya strobilacea and is typical of many of the amentiferae (e.g. Myricaceae, Betulaceae). The r-selected life-history pattern of the Platycarya line may well have contributed to its low diversity through geologic time.     

COMPARATIVE PALEOBIOCHEMISTRY OF SOME FOSSIL AND EXTANT FAGACEAE

A Fagus-like leaf fossil (cuticular compression) with an attached fruit, differing from any known Fagus species (fossil or extant) or other fagoid taxa, has been discovered from the Miocene Clarkia Lake deposits of northern Idaho. Because of its unusual morphology (especially the fruit) the fossil taxon has been described as a new genus and species, Pseudofagus idahoensis Smiley and Huggins. The successful previous use of paleobiochemistry in studies of fossil taxa from the Miocene Succor Creek Flora of Oregon suggested that chemical data might help clarify the taxonomic affinities of Pseudofagus. Indeed, examination of the chemistry of the fossil, Pseudofagus idahoensis, and comparison with extant Fagus species and related fagoid genera indicate that: 1) based on steroid chemistry, Pseudofagus idahonesis does belong in the Fagaceae; 2) like all extant species of Fagus, the fossil lacks the tannin component, ellagic acid, which separates it from other extant fagoid genera, and 3) its simple flavonoid pigment profile places it closest to the extant North American Fagus grandifolia or the European/Eurasian Fagus sylvatica. However, the exclusive presence of an isorhamnetin (3'-methoxyquercetin) 3-0-glycoside, onocerane, and 5α-cholestane imparts a species-specific chemical character to Pseudofagus idahoensis, which also sets it apart from extant species of Fagus. While the chemistry does not decide the taxonomic level to be accorded to the fossil, it certainly supports, along with morphology and anatomy, the distinctness of Pseudofagus and its proposed relationships within the Fagaceae.     

Female flower and cupule structure in Balanopaceae,an enigmatic rosid family

The Balanopaceae, whose flowers were poorly known, have, in the past, been variously allocated to the Fagales, Euphorbiaceae, Salicales or other hamamelids and rosids (these groups being in Fagales, Malpighiales and Saxifragales, according to the Angiosperm Phylogeny Group). This paper attempts a clarification based on flower morphology. Female flowers and cupules were studied in Balanops vieillardii, young fruits in B. australiana. The cupules are simple involucres of bracts which are spirally arranged (according to a Fibonacci pattern) on the floral axis preceding the flower. They contrast with the complicated cupules of Fagaceae which consist of a condensed cymose ramification system of axes of several orders around the flower. Flowers appear later than most of the cupular bracts, in contrast to Fagaceae. In addition to a terminal flower there may be several smaller lateral flowers in the axil of cupular bracts, each surrounded by its own small cupule. The female flowers do not have a perianth. They consist of two to three large carpels. At anthesis, the ovary is completely septate; the syncarpous part (ovary and lower style) is completely symplicate. The carpels are free for most of their length, with the free parts once, twice or three times bifurcate, in contrast to simple in Fagales. The stigmatic surface covers the ventral side of each stigmatic branch and at the margins also spreads to the dorsal side. The stigma is wet and secretion appears holocrine. The two ovules per carpel are collateral and axile in early development. However, at anthesis they appear one above the other, because in one ovule the funicle greatly elongates. As the ovary elongates only above the placenta, the ovules appear basal at anthesis. The ovules are (weakly) crassinucellar, bitegmic (not unitegmic), anatropous, and intermediate between apotropous and epitropous (not apotropous). The ovules are mature at anthesis, in contrast to Fagales. In mature ovules the upper part of the nucellus disintegrates, and a weakly differentiated endothelium is present in the inner integument. The morphological results of this study support a position of Balanopaceae in Malpighiales, and not Fagales or other orders, and are thus in accordance with recent molecular results based on chloroplast rbcL sequences data. However, within Malpighiales, as opposed to molecular results, Balanopaceae agree more with Euphorbiaceae s.l. than with Dichapetalaceae/Trigoniaceae and Chrysobalanaceae/Euphroniaceae.     

Dichilanthe, an unusual Asiatic Rubiaceae with "Lonicera flowers" and "dipterocarp fruits"

Dichilanthe, a disjunctly distributed, arborescent Southeast Asiatic genus (D. zeylanica: Sri Lanka; D. borneensis: West Borneo) with collar-like, persistent stipules, has strongly zygomorphic, ornithophilous flowers which show secondary pollen presentation. The curved corolla is two-lipped. The upper lip consists of 2, and the lower lip of 3 fused corolla lobes. The calyx, too, is zygomorphic. The curved, exserted style ends in a swollen “stylar head' which apically bears two small stigmatic (receptive) areas in a zygomorphic arrangement. The flowers are borne in compact, terminal heads, held together by enlarged stipules of a bract-pair immediately below the inflorescence. The dispersal units (diaspores) mimic dipterocarp fruits. They consist of a persistent, wing-like pair of bracts whose±cuplike stipules enclose the fruits. The diaspores break off at the node immediately below the bract-pair, where there is a distinct abscission zone. Initial on”primary“dispersal by wind may be followed by facultative”secondary“dispersal by floating in water.”Pith tissue“produced by each fruit of the diaspore, and the air spaces contained therein, are likely to be adaptations to floating. This”pith tissue“, a loose, parenchymatic,± irregularly arranged area of the fruit wall which partially disintegrates during fruit maturation, represents a modified portion of the endocarp; the remainder of the endocarp is”normal“sclerenchymatic tissue coating the two locules. The initial stages of this endocarp differentiation are already observable in early developmental stages, i.e., in ovaries of flower buds and open flowers. The bicarpellate ovaries contain a solitary, anatropous pendulous ovule per locule. Viable seeds have large embryos and only c. 5–6 layers of oily endosperm; their exotesta cells have delicate, ring-like thickenings. In developing fruits of individual inflorescences, a high frequency of seed abortion was noted. Not uncommonly, there is only a single viable seed per dispersal unit, i.e., only a solitary seedling emerging from a diaspore. Germination of the seeds is cryptocotylar. The pollen of D. zeylanica is suboblate and 5- or 6-colpate (with the colpi being rather short); the exine is finely reticulate. In spite of several of its character states being unusual and aberrant, the tribal position of Dichilanthe in the Guettardeae is not questioned, although it is concluded that the genus occupies a rather isolated position in the tribe.     

FACTORS LIMITING FRUIT AND SEED PRODUCTION OF A TEMPERATE SHRUB,STAPHYLEA TRIFOLIA L. (STAPHYLEACEAE)

Staphylea trifolia L., the bladdernut, is a self-incompatible temperate woodland shrub that flowers in May in Illinois. Factors limiting reproduction were studied at four levels: 1) Seeds/fruit. Seed production in open-pollinated fruit was frequently limited by too few fertilized ovules. Seed production in hand-cross-pollinated fruit was limited by resources or dispersal constraints: seed abortion rates were higher in hand-cross-pollinated fruits than in open-pollinated fruits. 2) Fruits/flower and 3) fruits/inflorescence. The number of fruits set and matured per flower and per infloresence in the open-pollinated treatment was limited by the number of flowers naturally cross-pollinated. In hand-cross-pollinated inflorescences, fruit set was not limited by resources even though fruit set was ten times greater than in the open-pollinated treatment. Evidence that resources limited fruit maturation in the hand-cross-pollinated inflorescences was equivocal. In hand-cross-pollinated flowers, fruit set was lowest when cold nights followed pollination, suggesting that cool temperatures limited postpollination physiological processes. 4) Fruits/individual. Early-flowering individuals matured fewer fruits than later-flowering individuals. Within the latter group, fruit production increased with plant size, although a relatively small individual matured the maximum number of fruits. Flowering phenologies and size of individuals varied among patches, resulting in differential reproductive success of patches.     

ANGIOSPERM PALEOBIOCHEMISTRY OF THE SUCCOR CREEK FLORA (MIOCENE) OREGON,USA

The organic chemical profiles of fossil Acer and Quercus leaf tissues are presented and correlated with those of previously described fossil Celtis, Ulmus and Zelkova and interpreted in conjunction with referable extant genera. Intrageneric comparisons among fossil and extant taxa indicate that relatively minor phytochemical differences exist suggesting that little flavonoid and steroid evolution since post-Miocene times has occurred. Biosystematic relationships between living North American and Asian genera indicate that in some cases (Quercus, Zelkova) a greater affinity exists between living Asiatic species and elements of the Succor Creek Flora. The chemical data are proposed as an independent parameter in assessing angiosperm biogeography and proposed migration patterns of the Fagaceae and Ulmaceae. The high chemical fidelity seen between some living and fossil genera preserved in ash-fall deposits is ascribed to the reaction of membrane bound lipids with various organic acids and to subsequent rapid dehydration.     

The Effects of Habitat on Dispersal Patterns of an Invasive Thistle, Cynara Cardunculus

Dispersal of offspring is a critical step in the spread of invasive species, yet dispersal patterns are seldom well studied, inhibiting effective management and ecological understanding of invasions. Dispersal patterns can be affected by characteristics of the parent plant and by climatic or site characteristics, including community vegetation structure, but these factors have not been studied in the context of plant invasion processes. Cynara cardunculus (L.) is a polycarpic perennial thistle invasive in coastal grasslands in California that produces large numbers of wind-dispersed seeds. This study quantified and compared C. cardunculus dispersal patterns in an exotic grassland (vegetated site) and an agricultural field (non-vegetated site). Seed size variation in C. cardunculus was also quantified within inflorescences, between inflorescences, and between years of production, and compared across dispersal distances. Results indicate that dispersal distance increased dramatically from less than 20 m in the vegetated site to more than 40 m in the non-vegetated site. Plants producing fewer seeds produced heavier seeds and dispersal distance decreased over time, but seed size was not related to dispersal distance, which may serve to spread the risk to seeds or seedlings across the environment. C. cardunculus has great potential for dispersal in open areas such as agricultural fields or disturbed sites, but may be limited in highly structured natural communities. Management of C. cardunculus and other wind-dispersed plant invasions may be improved by prioritizing populations with open or disturbed areas downwind and minimizing the removal of vegetation during dispersal.     

Inflorescence bracts of fossil and extant Tilia in North America,Europe, and Asia: patterns of morphologic divergence and biogeographic history

The enlarged inflorescence bract diagnostic of extant Tilia has an extensive Tertiary fossil record in the Northern Hemisphere. Diversity of bract morphology, and the extent of adnation between peduncle and bract, is reviewed for fossil and extant species of Tilia. An extinct type of bract with an orbicular outline and palmate venation is documented by the fossil species Tilia circularis (Chaney) comb. nov. from the early Oligocene of Oregon and is designated Type A. Living species of the genus have elongate bracts with predominately pinnate venation that are borne in two basic configurations: Type B, with the peduncle fused only to the extreme base of the bract lamina, as in extant Tilia endochrysea Hand.-Mzt. of southern China; and Type C with the peduncle fused medially along the basal one-third of the bract lamina, as in most extant species. Bracts of Type B were widely distributed in the Tertiary of western North America (late Eocene to Miocene) and Europe (early Miocene to Pliocene), while those of Type C are known in the fossil condition only from the middle and late Tertiary of Asia and Pliocene of Europe. The bracts of T. circularis, like those of type B, are borne on relatively long stalks and have the peduncle fused only at the extreme base. The fossil record supports recognition of the following characters as apomorphic in Tilia bract evolution: bracts sessile, peduncle adnate to the upper surface of the bract, and pinnate bract venation.     

INVESTIGATIONS OF ANGIOSPERMS FROM THE EOCENE OF NORTH AMERICA: JUGLANDACEOUS WINGED FRUITS

The winged fruits of Engelhardia have been reported in many early Tertiary floras in the northern Hemisphere. Recent systematic revisions of the extant genera, Engelhardia, Oreomunnea, and Alfaroa provide a helpful guide to the study of the fossil fruits. Fruit form, venation, nut septations and flower parts are features that separate the extant Asian Engelhardia from the American Oreomunnea. Four types of fossil winged fruits can be recognized in Middle Eocene sediments of southeastern North America: Engelhardia, Paraoreomunnea gen. n., Paleooreomunnea gen. n., and Pararengelhardia. Both Paleooreomunnea and Paraengelhardia represent extinct lines; no living forms have similar winged fruits. The fossil fruits of Engelhardia and Paraoreomunnea are similar to the fruits of extant Engelhardia and Oreomunnea, respectively. The fossil taxa reported in this paper were sympatric. The present allopatric distribution of Engelhardia and Oreomunnea is the result of Neogene regional extinctions. Engelhardia and Oreomunnea have probably been distinct genera since early Paleogene time.     

Origin, adaptive radiation and diversification of the Hawaiian lobeliads (Asterales: Campanulaceae)

The endemic Hawaiian lobeliads are exceptionally species rich and exhibit striking diversity in habitat, growth form, pollination biology and seed dispersal, but their origins and pattern of diversification remain shrouded in mystery. Up to five independent colonizations have been proposed based on morphological differences among extant taxa. We present a molecular phylogeny showing that the Hawaiian lobeliads are the product of one immigration event; that they are the largest plant clade on any single oceanic island or archipelago; that their ancestor arrived roughly 13 Myr ago; and that this ancestor was most likely woody, wind-dispersed, bird-pollinated, and adapted to open habitats at mid-elevations. Invasion of closed tropical forests is associated with evolution of fleshy fruits. Limited dispersal of such fruits in wet-forest understoreys appears to have accelerated speciation and led to a series of parallel adaptive radiations in Cyanea, with most species restricted to single islands. Consistency of Cyanea diversity across all tall islands except Hawai ;i suggests that diversification of Cyanea saturates in less than 1.5 Myr. Lobeliad diversity appears to reflect a hierarchical adaptive radiation in habitat, then elevation and flower-tube length, and provides important insights into the pattern and tempo of diversification in a species-rich clade of tropical plants.     

云南拉沙山黑白仰鼻猴对种子传播潜力的评估

灵长类是森林生态系统中植物种子的主要传播者,有助于森林植被的更新,然而受研究方法的限制,灵长类种子传播潜力常被低估。为全面评估温带灵长类动物的种子传播潜力,采用直接观察法和粪便分析法评估珍稀濒危灵长类动物黑白仰鼻猴的种子传播潜力。于2018年11月—2019年10月采用直接观察法(瞬时扫描取样法)收集云岭省级自然保护区拉沙山黑白仰鼻猴的活动时间分配数据,获取每月取食果实的比例;同时每月收集黑白仰鼻猴的粪便,采用粪便分析法分拣猴粪中残留的植物种子,统计有完整种子残留的月份和粪便比例,应用这两种方法评估黑白仰鼻猴种子传播潜力及其差异。结果表明：直接观察法收集到黑白仰鼻猴取食果实的月份数为6个月(7—12月),月均取食果实的比例为(15.31±20.15)%,共取食13种果实;而粪便分析法发现黑白仰鼻猴粪粒内全年都有完整种子残留,粪便中月均完整种子残留比例(35.19±35.43)%,其中9月至第二年1月粪便中种子残留比例都大于50%,共取食18种果实;综合两种方法发现云南拉沙山黑白仰鼻猴共取食20种植物果实,具有较高的种子传播潜力。直接观察法可确定黑白仰鼻猴取食果实的物种数,而粪便分析法能...     

EARLIEST MEGAFOSSIL EVIDENCE OF FAGACEAE: PHYLOGENETIC AND BIOGEOGRAPHIC IMPLICATIONS

Fossil evidence of Fagaceae from the Paleocene/Eocene boundary of western Tennessee is described and discussed. These fossils include a newly discovered pistillate inflorescence and dispersed fruits of subfamily Castaneoideae as well as a taxon that resembles modern trigonobalanoids (pistillate inflorescences and dispersed mature fruits). Fossil staminate catkins with fagaceous pollen, which we suggest may be conspecific with the trigonobalanoid infructescences, are also found at the locality. Two distinct types of fagaceous leaves are present at the locality. The reproductive structures are the oldest megafossils unequivocally assignable to Fagaceae and represent the oldest remains of subfamily Fagoideae and the oldest megafossil remains of Castaneoideae. In addition, the fossils provide insights into the chronology of diversification, biogeography, and phylogeny of Fagaceae. The trigonobalanoid remains may also provide insights into the timing and circumstances of the evolution of wind pollination in Fagaceae.