A NEW SPECIES OF PICEA BASED ON SILICIFIED SEED CONES FROM THE OLIGOCENE OF WASHINGTON

Picea eichhornii n. sp. is described from anatomically preserved seed cones. The fossils are from the Early Oligocene Jansen Creek Member of the Makah Fm. which is exposed along the northern shore of the Olympic Peninsula, Washington. The cones are at least 5.5 cm long and up to 3.5 cm in diameter. The cone axis is 4–6 mm in diameter and contains a pith made up of thick-walled parenchyma cells. Resin canals occur in a single ring in the secondary xylem in some specimens but are absent in others. The cortex is mostly parenchymatous and contains numerous large axial resin canals that branch to supply the bract and scale. Vascular traces to each scale and its subtending bract diverge separately from the vascular cylinder of the cone axis. The bract is tongue-shaped and keeled at its base. It is 5 mm wide and up to 9 mm long. The bract trace fades out before entering the bract base while two resin canals extend into the bract base. The ovuliferous scale is about 2.3 cm long and has a thin, probably papery, apex. Resin canals of the scale occur abaxial to the vascular tissue in the scale base, but some bend around the margins of the vascular strand to become adaxial outward. About 20 resin canals occur in the abaxial scale sclerenchyma, and this is the main anatomical feature that distinguishes these cones as a new species. There are less than 14 such canals in cones in a reference collection of 15 modern species and in the two fossil species known from anatomically preserved material. While the new species adds to our knowledge of the diversity of Cenozoic Picea, its affinities within the genus remain undetermined.     

PICEA WOLFEI,A NEW SPECIES OF PETRIFIED CONE FROM THE MIOCENE OF NORTHWESTERN NEVADA

Several silicified ovulate cones from the late middle Miocene (Barstovian) represent a new species, Picea wolfei Crabtree. This is the second species of Picea for which structurally preserved seed cones are known to be reported from the Tertiary. The cones are 5.0–8.0 cm long and 1.5–2.0 cm at their greatest diameter. Ovuliferous scales are inserted helically around the cone axis and are recurved at their point of divergence. Each scale is broadly obovate to spatulate with a rounded apex and bore two seeds adaxially. The bract subtending the scale is 4.5–7.3 mm long and is fused to the scale for 1.4–2.0 mm. Each bract has an inflated keel-like base which projects abaxially between the seeds of adjacent scales. The fossil cones superficially resemble those of the extant Picea breweriana, yet differ from them anatomically. The new species also resembles Picea lahontense, a fossil compression from the Miocene Trout Creek Flora of south-central Oregon, but the different modes of preservation preclude meaningful comparison. Picea diettertiana, the only structurally preserved fossil cone of this genus previously described, is quite dissimilar in that it lacks a sclerotic pith.     

PICEA DIETTERTIANA,A NEW SPECIES OF PETRIFIED CONES FROM THE OLIGOCENE OF WESTERN MONTANA

Fossils described in this treatment are the first structurally-preserved ovulate cones of Picea to be reported from the Tertiary. They are 5.0-5.8 cm long and 1.6-1.8 cm at their widest diameter. Numerous ovuliferous scales are arranged spirally around the axis and each bore two winged seeds. The bract subtending the scale is 4.0-7.0 mm long and is fused to the scale for 1.0 mm. The base of the bract is inflated on the abaxial side extending for about 1.0 mm between the seeds of the adjacent scales. Both the scales and their subtending bracts are recurved at their point of divergence from the axis. The ovuliferous scales taper gradually to a point, and the thickness of the tissues at the scale apex indicates that they were woody. Anatomically, the silicified cones are very similar to those of the Recent species and indicate that all important features of the latter had evolved by Oligocene time.     

STRUCTURE AND AFFINITIES OF ATHROTAXITES BERRYI BELL,AN EARLY CRETACEOUS CONIFER

Compressions and impressions of leafy twigs, pollen cones, and seed cones of Athrotaxites berryi are abundant in certain layers of the Kootenai Formation (Aptian) in Montana and the Lower Blairmore Formation in adjacent Alberta. The twigs are densely covered by helically arranged leaves that are about 2 mm long and wide. Pollen cones are borne laterally on ultimate branch segments. Some are sessile, while others terminate a minute lateral branch. The cones are 3–4 mm in diam and about 10 mm long. Each sporophyll has a stalk that is about 0.7 mm long and an upturned laminar tip that is 1–1.5 mm long by 1 mm wide. At least two pollen sacs are attached to the abaxial side of each sporophyll. Seed cones are borne terminally on lateral branches that are often curved. These cones are about 10 mm at their widest diameter and about 15 mm long. Each bract and associated ovuliferous scale are fused to form a wedge-shaped complex that is 4–5 mm long. The complex is 0.7 mm wide at its base and expands to about 2.5 mm wide and thick near its apex. The tip of the complex narrows abruptly to a point and terminates in a spine that is about 0.5 mm long. At least one seed occurs on the adaxial side of each complex. Athrotaxites berryi belongs to the Taxodiaceae. It resembles modern Athrotaxis cupressoides but differs from it in too many aspects to be included in the modern genus.     

A NEW TAXODIACEOUS SEED CONE FROM THE OLIGOCENE OF WASHINGTON

Cunninghamiostrobus goedertii is described as a new species based on permineralized seed cones from the Early Oligocene of Washington. The fossils come from the Makah Formation and were found on the northern shore of the Olympic Peninsula. The cone consists of numerous bract-scale complexes arranged helically around a central axis. Each bract-scale complex has a large bract bearing a small flap of tissue adaxially that represents the ovuliferous scale. Up to three seeds were produced on each complex. The vascular trace to the bract-scale complex diverges from the vascular cylinder of the cone axis as a concentric strand. This divides in the outer cortex of the axis to form a large collateral bract tract abaxially and a minute scale trace adaxially. The latter continues outward to supply the ovuliferous scale. The bract trace divides, forming many strands outward which occur in a row with transfusion tissue between them. Many resin canals also occur in the bract. The new cone combines features found in modern cones of Athrolaxis, Cunninghamia, and Taiwania but is most similar to Cunninghamiostrobus yubariensis from the Late Cretaceous of Japan.     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien. XII.Obirastrobus gen. nov., petrified pinaceous cones from the Upper Cretaceous of Hokkaido

Two new species of pinaceous cones belonging toObirastrobus gen. nov. are described from the Upper Cretaceous of Hokkaido. Bract-scale complexes are arranged helically and each consists of a small bract and a large scale. The bract and scale are separated. The scale tapers distally and its apex does not become papery. The anatomy of the bracts, scales, and seeds shows a combination of features unique in the Pinaceae and resembling those of the extant genusKeteleeria and the extinct genusPseudoaraucaria. Consecutive number from the previous paper (Ohsawaet al., 1992). Supported by Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture Nos. 63540545 and 02640533 to Makoto Nishida.     

ONTOGENY OF THE INFLORESCENCE OF SAURURUS CERNUUS (SAURURACEAE)

The spicate inflorescence of Saururus cernuus L. (Saururaceae) results from the activity of an inflorescence apical meristem which produces 200–300 primordia in acropetal succession. The inflorescence apex arises by conversion of the terminal vegetative apex. During transition the apical meristem increases greatly in height and width and changes its cellular configuration from one of tunica-corpus to one of mantle (with two tunica layers) and core. Primordia are initiated by periclinal divisions in the subsurface layer. These are “common” primordia, each of which subsequently divides to produce a floral apex above and a bract primordium below. The bract later elongates so that the flower appears borne on the bract. All common primordia are formed by the time the inflorescence is about 4.4 mm long; the apical meristem ceases activity at this stage. As cessation approaches, cell divisions become rare in the apical meristem, and height and width of the meristem above the primordia diminish, as primordia continue to be initiated on the flanks. Cell differentiation proceeds acropetally into the apical meristem and reaches the summital tunica layers last of all. Solitary bracts are initiated just before apical cessation, but no imperfect or ebracteate flowers are produced in Saururus. The final event of meristem activity is hair formation by individual cells of the tunica at the summit, a feature not previously reported for apical meristems.     

A NEW SCIADOPITYACEOUS SEED CONE FROM THE UPPER CRETACEOUS OF HOKKAIDO,JAPAN

A sciadopityaceous seed cone, Sciadopityostrobus kerae, gen. et sp. nov., is described on the basis of a permineralized specimen from the Upper Cretaceous (Cenomanian–Coniacian) of Hokkaido, Japan. The peel method was applied for anatomical observations. The seed cone consists of a cone axis receiving numerous cone scale complexes that are arranged helically. Each complex generally has five inverted ovules that are oriented adaxially. The cone is similar to those of living Sciadopitys verticillata with respect to its peltate cone scale complex, with free apices of both bract and ovuliferous scale, trichomes on the bract, and a trifurcated ovuliferous scale strand. In the fossil, the bract and ovuliferous scale strands fuse with each other in the basal part of the cone scale complex, while S. verticillata bract and ovuliferous scale strands are derived separately from the vascular cylinder and remain separate throughout their length. The present specimen is one of the oldest records of structurally preserved cones that can be assigned to the family Sciadopityaceae.     

PITYOSTROBUS PUBESCENS,A NEW SPECIES OF PINACEOUS CONES FROM THE LATE CRETACEOUS OF NEW JERSEY

This new species is based on a single semifusinized cone from the Late Cretaceous (Cenomanian) of New Jersey. The cone is flattened but essentially complete. It is 55 mm long and 8 by 13 mm in diam. Scale apices are thin, rounded, and entire, lacking evidence of an umbo or spine. The vascular cylinder of the cone axis is organized as a series of separate strands. The scale is made up of a basal portion that stands out nearly perpendicular to the cone axis and a sharply upturned distal portion. The bract base has a pronounced abaxial keel. Bract and scale traces diverge from the vascular cylinder of the cone axis separately from one another. A poorly developed interseminal ridge is present at the chalazal end of the seeds. An unusual feature of the cone is the presence of a trichome-bearing epidermis on the cone axis, bract-scale complex, and near the scale apex. Resin canals diverge into the bract-scale complex abaxial to the scale trace with branches becoming adaxial to the scale trace outward. A number of features of the new species occur in cones of Abies, Cedrus, Keteleeria, Larix, Picea, Pseudolarix, Pseudotsuga, and Tsuga as well as in the extinct genus Pseudoaraucaria. Features of Pinus are absent. This suggests that Pseudoaraucaria may have served as an ancestral source for modern genera other than Pinus with Pityostrobus pubescens representing an evolutionary intermediate.     

INFLORESCENCE AND FLOWER DEVELOPMENT IN THE PIPERACEAE. II. INFLORESCENCE DEVELOPMENT OF PIPER

The inflorescence development of three species of Piper (P. aduncum, P. amalago, and P. marginatum), representing Sections Artanthe and Ottonia, was studied. The spicate inflorescences contain hundreds or even thousands of flowers, depending on the species. Each flower has a tricarpellate syncarpous gynoecium and 4 to 6 free stamens, in the species studied. No sepals or petals are present. In P. marginatum the apical meristem of the inflorescence is zonate in configuration and is unusually elongate: up to 1,170 μm high and up to 480 μm wide during the most active period of organogenesis. Toward the time of apical cessation both height and diameter gradually diminish, leaving an apical residuum which may become an attenuate spine or may be cut off by an abscission zone just below the meristem. The active apex produces bract primordia; when each is 40–55 μm high, a floral apex is initiated in its axil. Both bract and floral apex are initiated by periclinal divisions in cells of the subsurface layer. The bracts undergo differentiation rather early, while the floral apices are still developing. The last-produced bracts near the tip of the inflorescence tend to be sterile.     

CONE AND OVULE DEVELOPMENT IN SCIADOPITYS (TAXODIACEAE-CONIFERALES)

Ontogeny of seed cones of Sciadopitys, with special reference to the ovule-supporting structure, is studied in material collected in Japan and Massachusetts. Cones are initiated as lateral or terminal structures in summer and complete the formation of most organs before winter. Bract development is well advanced before ovule-supporting structures are initiated. Continued cone development involves the formation of a narrow ridge of tissue in the axil of each fertile bract. This ridge develops a series of nine (but up to 12) apical lobes in centrifugal order, each of which is the primordium of a future tooth on the ovuliferous scale. Ovules are initiated as outgrowths of the adaxial surface of each lobe so that there is a one-to-one ratio between lobes and ovules. Intercalary extension of the ovuliferous scale itself (distally) and the common base of the bract and ovuliferous scale (proximally) greatly extends the complex. The ovuliferous scale eventually exceeds the subtending bract and its apex becomes recurved. Bracts each have a single trace, but each ovuliferous scale has a pair of traces that proliferate distally to irrigate ovule and scale lobe. Intercalary growth results in recurvature of the ovule trace. The organization of the cone is directly comparable with certain Permian fossils. Sciadopitys also seems unique within the Taxodiaceae in its centrifugal development of the ovule-supporting complex.     

BIFURCATION OF THE STEM APEX IN ASCLEPIAS SYRIACA

In Asclepias syriaca the overall inflorescence is an anthoclad in which the peduncles are non-axillary, each occurring about 60° away from the axil of a leaf. Ontogenetically, a peduncle is initiated when the stem apex expands laterally and bifurcates into separate apices, neither of which is subtended by any type of organ. One of the two apices continues as the functional apex of the stem (bifurcating again at each subsequent node), and the other functions as the apex of the peduncle. The peduncle first produces a bract and, then, a pedicel in the axil of the bract. Subsequent pedicels are each axillary to separate bracts. The pedicels, therefore, can be interpreted as ordinary lateral branches. However, because the bifurcations of the stem apex are not associated with subtending organs, the branching of the stem does not conform to expected monopodial or sympodial systems in the angiosperms. This suggests the possibility that each bifurcation of the stem apex is a true dichotomy. The anthoclad axis, thus, is a series of dichotomies. Although such a series may have been phylogenetically derived from a monopodial or sympodial ancestor, it is also possible that it may have been retained from a primitive, dichotomizing inflorescence.     

TAXONOMIC CHARACTERISTICS OF SPHENOPHYLLALEAN CONES

The range of variability in the taxonomic characteristics traditionally used to establish genera and species of Sphenophyllum cones is studied from specimens of Bowmanites dawsoni, B. trisporangiatus, B. bifurcatus, Litostrobus, and Sphenostrobus. Taxonomic criteria examined include configuration of the cone stele, number of sporangiophores per bract, anatropous vs. orthotropous sporangium attachment, number of appendages per node, and spore morphology. Because of the large degree of variability observed, these characteristics do not appear to adequately differentiate between the genera Litostrobus and Sphenostrobus, so these genera are combined under Sphenostrobus. A new combination, S. iowensis, is proposed for specimens previously described as L. iowensis, L. paulus, and B. moorei. It is suggested that species currently placed in the genus Bowmanites may represent several distinct natural genera of sphenophyllalean cones.     

CONE AND OVULE ONTOGENY IN TAXODIUM AND GLYPTOSTROBUS (TAXODIACEAE – CONIFERALES)

Seed cones in Taxodium distichum and Glyptostrobus pensilis occupy the position of permanent shoots and are initiated in the summer preceding spring pollination. Morphological features are similar in the two genera, reflecting their close taxonomic relationship. Ovule complexes originate as two (rarely more) ovule primordia in the axil of each fertile bract but without any indication of a preceding discrete ovuliferous scale. When the nucellus, integument, and micropyle are well developed, a series of up to ll abaxial lobes forms at the base of each ovule pair. They become fused by basal growth. After pollination the common basal meristem of lobes and bract extends by intercalary growth to form the conspicuous “ovuliferous scale” of the mature cone; the lobes enlarge and exceed the ovules. Despite the topographic similarity in the cones of both genera, there are differences in vasculature such that the vascular traces to the axillary complex originate directly from the axial cylinder in Glyptostrobus but from the bract trace in Taxodium. The complex vasculature of the mature cone develops late and primarily as an expression of intercalary growth.     

REPRODUCTIVE BIOLOGY OF THE CERRO CUADRADO (JURASSIC) FOSSIL CONIFERS: PARARAUCARIA PATAGONICA

Seventy-two silicified cone specimens of Pararaucaria patagonica Wieland from the Cerro Cuadrado (Jurassic) petrified forest in Patagonia were studied by use of thin sections and reflected light. Traces from the cone axis stele to the bract and ovuliferous scale are separate at their origins. In cross section the abaxially concave ovuliferous scale trace and massive circular bract trace branch half-way out into the cone-scale complex. Two triangular-shaped bundles of fibers follow the scale trace into the laminar part of the ovuliferous scale. Both surfaces of the ovuliferous scale possess hairs which may have assisted in cone closure. Cones typically contain one flattened, winged seed per ovuliferous scale. Multi-layered seed integuments are represented by an inner fleshy layer of large cells filled with a black amorphous material, a sclerotesta consisting of wedges or fan-shaped groups of sclereids oriented at right angles to the seed surface, and a thin, often crushed fleshy layer. Seed wings consist of anastomosing, branched cells resembling glandular hairs and containing many intercellular spaces. Well-preserved polycotyledonous embryos containing up to eight cotyledons are present in several cones. Tissues of the embryo including the shoot apex, calyptroperiblem, hypocotyl, and cotyledons are described. On the basis of anatomical and morphological features, specimens of P. patagonica are compared to members of both extant and extinct families of conifers including the Araucariaceae, Taxodiaceae, Pinaceae, Cupressaceae, and Cheirolepidaceae.     

STRUCTURE AND DEVELOPMENT OF THE PERIANTH IN DOWNINGIA BACIGALUPII

The structure and ontogeny of the calyx and corolla of Downingia bacigalupii Weiler (Campanulaceae; Lobelioideae) were investigated for the purpose of comparing perianth development with previous observations on the floral bract, as well as elucidating the mechanism of development of the zygomorphic, sympetalous corolla. Sepals are uni-traced with a palmate, reticulate venation. They have basal and apical hydathodes, as well as storage tracheids. Sepals show a reduction in size, venation and hydathode number when compared to the bract. The pentamerous, zygomorphic corolla is bilabiate, consisting of a three-lobed adaxial lip and a two-lobed abaxial lip connected by a short tubular region. The constituent petal lobes are also uni-traced and have a reticulate venation, resembling that of the sepal and bract, but lack storage tracheids and hydathodes. Sepals arise in an adaxial to abaxial succession and are initiated in the outer corpus layer of the floral apex. Expansion of the floral apex follows and is accompanied by the establishment of a second tunica layer. Sepals undergo apical, marginal, and intercalary growth accompanied by acropetal differentiation of procambium. The petals arise simultaneously and are initiated in the second tunica layer and the outer corpus cells. After initiation, the petals exhibit a period of apical and marginal growth followed by intercalary growth. Apical growth in petals is less protracted than in sepals, but plate meristem activity is more extensive. The free petal lobes become temporarily fused by an interlocking of marginal epidermal layers, but they separate at anthesis. Zonal growth beneath the originally free lobes forms the tube and lip regions of the sympetalous corolla. Zygomorphy is evident from the time of initiation of petals and is accentuated by later differential growth. Comparative observations of corolla ontogeny in autogamous species of Doumingia indicate that the reduced corollas in these taxa are derived by a simple process of neoteny.     

FERTILE CONIFEROPHYTE REMAINS FROM THE LATE TRIASSIC DEEP RIVER BASIN,NORTH CAROLINA

Seed cones (Compsostrobus neotericus gen. et sp. nov.), pollen cones, and vegetative remains of coniferophytes occur in Upper Triassic rocks of the Deep River Basin (Pekin Formation) of Central North Carolina. Seed cones have spatulate ovuliferous scales, each with two ovules and subtended by an elongated bract with an attenuate tip. Cuticle of seed cones resembles that of leaves on vegetative axes. Slender leaves are borne along two sides of the axis. Pollen cones have helically arranged microsporophylls, each with two abaxial sporangia bearing pollen grains of the Alisporites type. Seed cones, pollen cones, and vegetative remains suggest a coniferophyte very modern in aspect.     

SILICIFIED PINUS REMAINS FROM THE MIOCENE OF WASHINGTON

Silicified leaves, dwarf shoots, pollen cones, and seed cones of Pinus from a Late Miocene chert bed within the Yakima Basalt Formation near Yakima, Washington are interpreted as coming from a single new species, P. foisyi. The needles and dwarf shoots are those of a three-needle pine. The needles contain two to four medial resin canals, a biform hypodermis, and endodermal cells with uniformly thickened walls. The pollen cones are ellipsoidal and about 1 cm long, and many contain bisaccate pollen grains. The seed cones are at least 6 cm long and are slightly asymmetrical. The cone axis has a broad sclerotic outer cortex, and the seed wing extends from a thick parenchymatous base. The scale apex bears a conspicuously swollen projection. The foliage and seed cones are identifiable with the Subgenus Pinus, Section Pinus, Subsection Oocarpae independently of one another, and together indicate a fossil species related to the modem Californian closed cone pines. Pinus foisyi represents one of the earliest occurrences of cone asymmetry associated with this group. However, cone serotiny characteristic of the modem species appears to have evolved after the Late Miocene.     

INFLORESCENCE AND FLOWER DEVELOPMENT IN THE PIPERACEAE III. FLORAL ONTOGENY OF PIPER

Floral development in Piper was compared between four-staminate species (P. aduncum and P. marginatum) and six-staminate species (P. amalago). All Piper species have a syncarpous gynoecium composed of three or four carpels. The floral apex is initiated by a periclinal division in the subsurface layer in the axil of a bract 40-55 μm high; initiation of the bracts occurs separately and considerably earlier. The floral primordium widens and the first pair of stamens are initiated at either side. The median anterior stamen forms next, and the median posterior later. This sequence is common to all species studied. In the six-staminate P. amalago, the last two stamens form simultaneously in lateral-anterior positions. The stamens hence arise as pairs, and symmetry is bilateral or dorsiventral. The three or four carpels arise simultaneously; they are soon elevated on a gynoecial ring by growth of the receptacle below the level of attachment of the carpels to produce a syncarpous gynoecium. The floral apex lastly produces the solitary basal ovule and is used up in its formation.     

INFLORESCENCE AND FLORAL DEVELOPMENT IN HOUTTUYNIA CORDATA (SAURURACEAE)

The inflorescence of Houttuynia cordata produces 45–70 sessile bracteate flowers in acropetal succession. The inflorescence apical meristem has a mantle-core configuration and produces “common” or uncommitted primordia, each of which bifurcates to form a floral apex above, a bract primordium below. This pattern of organogenesis is similar to that in another saururaceous plant, Saururus cernuus. Exceptions to this unusual development, however, occur in H. cordata at the beginning of inflorescence activity when four to eight petaloid bract primordia are initiated before the initiation of floral apices in their axils. “Common” primordia also are lacking toward the cessation of inflorescence apical activity in H. cordata when primordia become bracts which may precede the initiation of an axillary floral apex. Many of these last-formed bracts are sterile. The inflorescence terminates with maturation of the meristem as an apical residuum. No terminal flowers or terminal gynoecia were found, although subterminal gynoecia or flowers in subterminal position may overtop the actual apex and obscure it. Individual flowers have a tricarpellate syncarpous gynoecium and three stamens adnate to the carpels; petals and sepals are lacking. The order of succession of organs is: two lateral stamens, median stamen, two lateral carpels, median carpel. The three carpel primordia almost immediately are elevated as part of a gynoecial ring by zonal growth of the receptacle below the attachment of the carpels. The same growth elevates the stamen bases so that they appear adnate to the carpels. The trimerous condition in Houttuynia is the result of paired or solitary initiations rather than trimerous whorls. Symmetry is bilateral and zygomorphic rather than radial. No evidence of spiral arrangement in the flower was found.