THE NATURAL AFFINITY OF THE CARBONIFEROUS SEED,CALLOSPERMARION

A seed of Callospermarion pusillum has been found attached to a long slender stalk. Significant features of the seed based upon additional specimens are described. Secretory cavities in the integument are similar to those in the stem of Callistophyton poroxyloides and the fertile foliage bearing the pollen organ Callandrium callistophytoides. Vesicaspora sp. pollen similar to that found in Callandrium, occurs in the pollen chamber. Callistophyton, Callandrium, and Callospermarion are considered to represent the detached organs of a new seed fern family, Callistophytaceae.     

A FERTILE AXIS OF TRILOBOXYLON ASHLANDICUM,A PROGYMNOSPERM FROM THE UPPER DEVONIAN OF NEW YORK

A partially petrified impression of Triloboxylon ashlandicum (Aneurophytales) is the first recognized fertile axis of the genus. Identification of the fertile axis rests on the similarity of its anatomy with that of previously described vegetative specimens. Fertile organs replace some vegetative branches along part of the main axis. Fertile organs are twice dichotomized in one plane and bear elongate sporangia arranged pinnately. Vegetative branches differ in that they bear the ultimate appendages of the plant helically. The latter organs dichotomize many times in one plane. Although similar in size and morphology to the ultimate appendages, the fertile organs are homologous by position and vascular supply to the vegetative branches which they replace. Sporangia of T. ashlandicum dehisce longitudinally and terminate in an apiculate tip. Spores are unknown. Fertile organs of T. ashlandicum resemble those of other Aneurophytales and support the earlier placement of Triloboxylon in the order on anatomical grounds. T. ashlandicum differs from other Aneurophytales, however, by bearing vegetative organs at the distal end of its fertile axis.     

THE MORPHOLOGY AND RELATIONSHIPS OF RHODEA,TELANGIUM, TELANGIOPSIS,AND HETERANGIUM

This study deals with four form or organ genera from the Upper Mississippian (Chester Series) of the Illinois Basin, and provides evidence that they were produced by a single natural genus with gymnospermous affinity. The plant remains—compressions, impressions, petrifactions, and specimens that combine compression or impression with petrifaction—allow examination of both external morphology and internal anatomy. The specimens include foliage corresponding to Rhodea, stems and petioles corresponding to Heterangium, and synangiate fructifications corresponding to either Telangium or Telangiopsis. The stems and foliage are considered parts of the same plant because of the identity of the anatomical and cuticular features of petioles attached to stem and those petioles with attached foliage. The fertile material is regarded as part of the same plant because: (1) The anatomy of axes of the fertile specimens is like that of the sterile specimens. (2) A single specimen may contain both sterile Rhodea-type axes and fertile regions. (3) Axes bearing synangia have the same size and patterns of divisions as the sterile foliage. Features that indicate lyginopterid affinities include: (1) Equal forking of the petiole. (2) Presence of fiber bands in the outer cortex and sclerotic nests in the inner part of the cortex. (3) Crowded circular bordered pits on the lateral walls of the metaxylem tracheids. (4) The presence of a small amount of secondary xylem. A variety of structural details of the stem and petiole suggest the genus Heterangium. The phyletic position of the plant that produced Rhodea, Telangium, Telangiopsis, and Heterangium is reviewed in light of such discoveries as the presence of a planated frond that lacks a lamina and the presence of both monolete and trilete microspores in a single synangium.     

Aluminum,Fe, Ca,Mg, K,Mn, Cu,Zn and P in above- and belowground biomass. I.Abies amabilis andTsuga mertensiana

In a mature mixed subalpine stand ofTsuga mertensiana andAbies amabilis, significantly higher Al levels were found in foliage, branch and root tissues ofT. mertensiana.Tsuga mertensiana had significant increases in Al, Ca and Mn levels with increasing foliage age. In current foliage,T. mertensiana had lower levels of Ca, similar levels of Mg and P, and higher levels of Mn thanA. amabilis. Both tree species had Cu and Fe present at higher levels in branch than foliage tissues. Fine roots had the highest concentrations of Al, Fe and Cu but the lowest Ca and Mn concentrations of all tissues analyzed. In the roots of both species, phloem tissues always had significantly higher Al levels than xylem. Fine roots (< 1 and 1–2 mm) ofT. mertensiana had higher Al levels than were found inA. amabilis. Roots greater than 2 mm in diameter exhibited no significant differences in Al levels in phloem or xylem tissue betweenA. amabilis andT. mertensiana. The two species show a clear difference in their ability to accumulate specific elements from the soil.     

POLLEN ORGANS OF THE PENNSYLVANIAN CALLISTOPHYTACEAE (PTERIDOSPERMOPSIDA)

Numerous specimens of the pteridospermous pollen organs Idanothekion glandulosum and Callandrium callistophytoides are present in Middle and Upper Pennsylvanian petrifaction material, respectively. Several specimens of Idanothekion, previously known only in an isolated condition, are attached to foliage assignable to the monostelic seed fern Callistophyton. Proof of the affinities of Idanothekion allows this genus to be elevated from a form genus to an organ genus in the Callistophytaceae. The structure of the foliage and the mode of attachment of the Idanothekion specimens are like those previously described for Callandrium. Structural features of Idanothekion and Callandrium are compared, and the question of their identity is discussed. At present one basic type of pollen organ, borne on the abaxial surface of foliar pinnules, is known for members of the Callistophytaceae.     

Foliage Density of Branches and Distribution of Plant‐Dwelling Spiders1

We compared the abundance of foliage‐living spiders among seven widespread plant species comprising a gradient of levels of structural complexity in a tropical savannah‐like region in southeastern Brazil. Spider abundance among plant species was positively related to the foliage density of their branches. A field experiment using artificial branches was carried out to isolate foliage density effects on spider abundance, thus controlling both biomass and texture effects. Artificial branches were attached to branches of three plant species with similar foliage density, Baccharis dracunculifolia, Diplusodon virgatus, and Microlicia fasciculata. Two treatments were set up: artificial branches with higher foliage density attracted more spiders than those with lower foliage density. The guild structure of hunting spiders was compared among vegetative branches of three plant species with different levels of foliage density: B. dracunculifolia, D. virgatus, and Bidens gardneri. Stalker, and ambusher spiders were more abundant on branches of B. dracunculifolia, which had the highest foliage density. Foliage‐runners constituted the dominant guild on D. virgatus and B. gardneri, which have lower foliage density branches. Our results suggest that branch architecture is the most important factor determining the abundance of plant‐dwelling spiders in the study area independently of branch biomass, leaf surface area or texture.     

STUDIES OF PALEOZOIC MARATTIALEANS: AN EARLY PENNSYLVANIAN SPECIES OF THE FERTILE FERN SCOLECOPTERIS

Remains of the fossil Marattiales are very rare in Lower Pennsylvanian sediments. The present report describes a new species of the fertile fern foliage Scolecopteris from the Lewis Creek, Kentucky locality (Lower or lower Middle Pennsylvanian). Scolecopteris conicaulis n. sp. has radial synangia composed of a ring of 4–7 elongate, exannulate sporangia. Most features of the synangia of S. conicaulis were previously hypothesized to be primitive in Scolecopteris based on geologically younger species. Supposed primitive characters include the large synangium pedicel with fiber core, an outer-facing sporangial wall lacking differentiation or zonation, and large spores. The anatomy of the sporangium walls, pinnule morphology, and general spore type support an association with the Minor group of Scolecopteris. The new species is similar in several important features to Scolecopteris (Cyathotrachus) altus, the only other anatomically preserved fertile marattialean known from this early time, and indicates a considerably earlier origin for fertile foliage of this type.     

Re-evaluation of Halle’s fertile pteridosperms from the Permian floras of Shanxi Province, China

In 1927, T. G. Halle published an extensive synthesis of the Permian fossil plant assemblages from China’s Shanxi Province that included five genera and species of seed plant that either had ovules in organic attachment or closely and repeatedly associated with foliage. These fertile pteridosperms were the subject of a later publication (1929) that provided additional information on each species, but since that time only Nystroemia pectiniformis Halle has been subjected to detailed investigation based on the original materials. Reinvestigation of the remaining four species has yielded additional examples and new information for each species, and has confirmed the pteridospermalean affinity for three of the four species. Alethopteris norinii Halle shows organic attachment of a pollen organ similar to Wittleseya (Newberry) Halle and is reinterpreted as a microsporangiate medullosan pteridosperm. Emplectopteris triangularis Halle and Sphenopteris tenuis (Schenk) Halle both bear numerous ovules attached directly to the leaf laminae, with Emplectopteris conforming with the gross-organisation of callistophytalean pteridosperms and S. tenuis being interpreted as a derived lagenostomalean pteridosperm. However, discovery of the counterpart to the key specimen of Pecopteris wongii Halle that Halle interpreted as bearing ovules demonstrates this species to be a sterile marattialean frond that agrees with its assignment to Pecopteris. In addition, two further specimens are demonstrated to be fertile organs of previously unknown pteridosperms; Norinosperma shanxiensis gen. et sp. nov. bears cardiocarpalean ovules abaxially on the proximal portions of the frond with ovules positioned directly on the veins of a leaf lamina; Norinotheca shanxiensis gen. et sp. nov. bears large pollen organs abaxially and singly on the vein of the leaf lamina. Collectively Halle’s pteridosperms remain important today as they are some of the few specimens that actually demonstrate organic connection of fertile organs to foliage, helping to characterise the morphology and organisation of this seed plant group. These species also demonstrate the persistence of seed plant families and genera in the Permian of China that became regionally extinct at the end of the Carboniferous in Euramerica, and show that pteridosperms remained an important component of Permian as well as Carboniferous floras globally.     

A new microsporangiate organ from the Lower Carboniferous of the Novgorod Region,Russia

A new species of the genus Telangiopsis, T. nonnae O. Orlova et Zavialova, was described on the basis of a microsporangiate organ from the Lower Carboniferous deposits of the Novgorod Region. The morphology of branching fertile axes, synangia, and sporangia was thoroughly studied. The three-dimensional system of fertile axes branches monopodially; ultimate axes bear numerous connivent bunches of synangia, which consist of three to six basally fused elongated ovate sporangia. The morphology and ultrastructure of prepollen grains were studied, which were extracted from the rock matrix surrounding the sporangia. The two-layered exine includes a well-developed endexine and an alveolate ectexine, with one-three rows of large thin-walled alveolae. The new species was compared with other Early Carboniferous microsporangiate organs.     

The Early Carboniferous progymnosperm Protopitys: new data on vegetative and fertile structures,and on its geographic and stratigraphic distribution

We review progress made during the last 25 years in our understanding of the Protopityales, Early Carboniferous plants belonging to the extinct group of the progymnosperms. Recent studies support previous observations that the only genus of this order, Protopitys, included large arborescent plant with trunks up to 1 m in diameter. All branch orders had an oval eustele, secondary xylem with small rays and tracheid pitting ranging from circular bordered to scalariform bordered, and vascular traces to lateral appendages emitted in an alternate to subopposite distichous arrangement. Leaf morphology remains unknown. New material also confirms that fertile organs of Protopitys consist of branching systems bearing elongated sporangia terminally. Spores have a perispore and range in two size groups, which has been interpreted as a primitive stage of heterospory. The dense wood and fertile parts of Protopitys are comparable to those of the aneurophytalean progymnosperms of the Devonian, but Protopitys is distinct by its eustelic primary vascular system, and its affinities are still uncertain. The genus is now documented from at least nine localities in Europe, North America and Australia. Recent discoveries also indicate that it was present through the whole Mississippian, from the middle Tournaisian to the Serpukhovian.     

LEAF DEVELOPMENT IN SCHIZAEA AND ACTINOSTACHYS

Observations on the initiation and growth of the fertile digits and of their assemblages in Schizaea and Actinostachys as well as of the entire frond in S. dichotoma are presented. The leaf of S. dichotoma, although dichotomous in appearance at maturity, goes through a series of dichotomous and lateral ramifications during ontogeny. It is compared with the entire frond (“aerial shoot”) of Psilotum nudum. The sporangiate fructifications of Schizaea develop as their mature form suggests, i.e., by acropetal initiation and development of pinnately arranged digits. The counterpart in Actinostachys, irrespective of fertile digit number, develops as only three pinnae, two lateral and one terminal. It cannot be said, therefore, that the condition in Actinostachys, i.e., the digitate arrangement of fertile parts, is fundamentally the condition which exists in Schizaea but with a very short rachis. The fundamental difference is in pinna number and frequency of dichotomies which establish the final digit number.     

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.     

Juvenile/total foliage ratios inEucalyptus nitens and the growth of stands and individual trees

Summary Individual trees and stands of two provenances of Eucalyptus nitens which have marked differences in retention of juvenile foliage were studied in four plantations at different elevations. The proportion of juvenile to total foliage and growth was measured at the end of the 2nd, 3rd and 4th year from establishment. Between the ages of 2 and 4 years annual stem volume increment increased in proportion to the amount of juvenile foliage retained. By age 4 years, stem volume of trees of the juvenile persistent form was significantly larger than that of the early adult form. Increasing differences in height growth with age between provenances, which were highly significant across sites by age 4, contributed to these differences in performance. There was some evidence that the largest trees of the juvenile-persistent form were those which combined mature foliage above juvenile foliage for the longest period during the transition from juvenile to mature foliage. In the early-adult form the largest trees were those which completed the transition to mature foliage rapidly. There was no difference in the ratio of foliage mass to basal area between the two forms. It is suggested that the faster growth of the juvenile-persistent form is related to higher leaf area index and not to foliage type. A provenance of E. globulus which had a higher retention of juvenile foliage at age 4 than a second provenance had a lower stem volume, thus indicating that in this species early growth rate is not determined by foliage type.     

CALAMOPHYTON PRIMAEVUM: THE COMPLEX MORPHOLOGY OF ITS FERTILE APPENDAGE

Although holotype material of Calamophyton primaevum Kläusel and Weyland has not been available since the Second World War, two fertile specimens of that species are in the personal collection of Professor H. Weyland. The purpose of this paper is to disclose the complexity of the organization of the fertile appendage. Formerly it was believed to consist of one segment that had dichotomized once and that had borne two pendulous sporangia, one at each branch. Numerous degagements of sporangia have revealed a complex morphology, consisting of one main segment divided into two secondary segments. Each supports three recurved side stalks which in turn bear 2 sporangia, a total of 12 sporangia. Each secondary segment terminates in two elongated projections. The morphology of the fertile organs is compared with that of two other species, C. bicephalum Leclercq and Andrews and C. forbesii Schopf. Great similarity of organization exists between C. primaevum and C. bicephalum. The possible synonymy of these two species is discussed.     

VEGETATIVE AND FERTILE STRUCTURES OF CYATHOTHECA VENTILARIA FROM THE UPPER PENNSYLVANIAN OF THE APPALACHIAN BASIN

Permineralized stems, leaves and a fertile structure assignable to Cyathotheca Taylor are described from the Late Pennsylvanian Duquesne Coal of eastern Ohio. The new material, C. ventilaria sp. nov., provides the first evidence of vegetative structures for the genus. Vegetative parts are referred to the fertile fragments based upon distinctive vascular morphology, common histological features, and close association. Stems are up to 5.0 mm in diam and have an apparently endarch dictyostele with scalariform metaxylem tracheids. Secondary xylem consists of tracheids with bordered pitting and uniseriate, parenchymatous rays 1–9 cells high. Leaves are arranged in a 3/8 pattern. They are small, pinnately-lobed, and vascularized by an U-shaped bundle. Distal to divergence, one of the apparent leaf traces becomes radial to resemble the base of a fertile structure. This implies a mode of attachment for the fructification and suggests evidence to interpret its homologies. The fertile specimen consists of laminae that diverge from a short stalk, and bifurcate distally. Laminae bear sporangia 0.6–0.7 mm in diam attached adaxially by vascularized pedicels. Spores average 36 μm in diam and are of the Kewaneesporites type. The combination of features now known for Cyathotheca exclude it from assignment to a currently-recognized major group of vascular plants, thus emphasizing that the Pennsylvanian coal swamp flora included a greater diversity than commonly is interpreted.     

ARCHAEOPTERIS MACILENTA,ANATOMY AND MORPHOLOGY OF ITS FROND

The stem, rachides, and pinnae of Archaeopteris macilenta, formerly considered to be a fern of Devonian age, comprise a branch system in which the ultimate divisions heretofore referred to as pinnules are the leaves. The primary vascular system of the “frond” is a lobed siphonostele from which leaf traces arise in a spiral sequence. The anatomy of the “rachis” and of the “pinnae” is shown to be similar to that of the stem, Callixylon, which bore these “fronds.” Branching, epidermal pattern and stomates are described for the spirally arranged leaves (fertile pinnules). Attachment and dehiscence of sporangia as well as their stomates are reported. Archaeopteris is retained in the Class Progymnospermopsida which includes plants with gymnospermous anatomy and pteridophytic reproduction. It is suggested that Actinopodium, Svalbardia and Siderella are related closely to Archaeopteris and that this group of genera shows evolutionary stages in webbing of leaves and planation of branch systems. The opportunities for ontogenetic studies of the arborescent genus Archaeopteris are pointed out.     

STUDIES OF PALEOZOIC MARATTIALEANS: THE MORPHOLOGY AND PROBABLE AFFINITIES OF TELANGIUM PYGMAEUM GRAHAM

Telangium pygmaeum Graham is known from Upper Pennsylvanian coal balls from the Calhoun coal mine (Illinois). The species was described as possessing radial synangia consisting of 3-5 sporangia fused laterally for about f13 their length. Synangia were believed to be sessile and borne terminally or laterally on a branching rachis without lamina. Examination of new coal ball material of the same age indicates that the synangia are borne abaxially on the pinnules of a compound frond with the anatomy of a Psaronius leaf (Marattiales). Synangia are sessile and borne in two rows, one on either side of the pinnule midrib, under the unbranched lateral veins. Synangia are radial, 0.6 mm in diam, and consist of a ring of thin-walled sporangia fused to near their apices prior to dehiscence, but separating on dehiscence to release spores along their inner midline. Spores are spherical, trilete, 30-48 μm in diam, with a granulate ornamentation. The new genus Araiangium is proposed for this material based on the organization of the sessile thin-walled synangia. Araiangium is compared with other marattialean genera with sessile synangia (Acaulangium, Acitheca), and with the pedicellate synangia of various species of Scolecopteris. Criteria used in the delimitation of genera in Paleozoic anatomically preserved marattialean fertile foliage are discussed.     

SYMMETRY AND DEVELOPMENT OF LIMNOBIUM SPONGIA (HYDROCHARITACEAE)

Limnobium spongia produces upright vegetative axes and prostrate stolons. The upright axes bear new stolons, whereas the stolons bear new upright axes and fertile and sterile branching systems. Upright axes and fertile and sterile branching systems are all interpreted to have sympodial growth. However, it was not determined whether growth of stolons is monopodial or sympodial. Both stolons and upright axes branch in alternate plastochrons, and branching is achieved solely by the bifurcation of apical meristems. Each meristematic bifurcation is interpreted to represent the formation of a precocious lateral bud. The upright axes develop from presumed precocious lateral buds on stolons, whereas such buds on upright axes produce renewal shoots. Limnobium spongia exhibits a marked degree of mirror-image symmetry.     

THE CRETACEOUS PTERIDOSPERMS RUFLORINIA AND KTALENIA AND IMPLICATIONS ON CUPULE AND CARPEL EVOLUTION

The vegetative (Ruflorinia sierra) and fertile (Ktalenia circularis) organs of an Early Cretaceous pteridosperm collected from Santa Cruz Province in Argentina are described. The sterile leaf is at least tripinnate and bears decurrent secondary pinnae with obliquely attached, sharply pointed pinnules. The fertile member arises from the base of the vegetative rachis and bears two types of appendages, cupules and bracts. Bracts are attached to the main axis near cupules and are present in clusters of up to six. Cupules are sessile, spherical, and arranged in opposite or subopposite pairs along the axis. A small lip is present on one surface of the cupule. The number of seeds per cupule may be one or two, with each characterized by a distal nucellar beak and circular, chalazal scar. Cuticular anatomy, including the fine structure of the stomatal complex, is described for both vegetative and reproductive organs. The cupules of Ktalenia and other Mesozoic seed plants are compared, and a discussion presented regarding the possible function of the cupule.     

Two-criteria model assessment shows that foliage maintenance in old-growth Pseudotsuga menziesii requires both delayed and sequential reiteration

Functional structural models (FSMs) are valuable tools to explore relationships between plant form and function, yet they lack rigorous methods for development and assessment. We use multi-criteria assessment of an architectural FSM to show that both traumatic sequential and adaptive delayed reiteration (ADR) are necessary components of foliage maintenance in branches of old-growth Pseudotsuga menziesii. ADR has previously been established as a process that maintains foliage in old-growth P. menziesii. We use a simulation model of branch development in the species to evaluate morphogenesis in the context of this ADR. The structure of the model is a theoretical representation of how P. menziesii branch morphology develops throughout the branch lifespan, and this model structure is assessed with two criteria that are optimized simultaneously; the criteria measure foliage demography by the number of foliated shoots, and how those foliated shoots are organized into independent clusters. Assessment results indicated that improvements in model structure were required. Anomalous parameter vectors from the assessment search uncovered an inadequacy in the process of foliage maintenance, and the model was modified to include traumatic sequential reiteration in addition to ADR. The modes of the resulting parameter distributions were consistent with empirical observations. We discuss why the assessment of FSMs is an essential procedure that requires multiple criteria.