Search

The recently described fossil angiosperm genus Eophylica (Rhamnaceae) was based on 18 amber-embedded specimens derived from two sites in northern Myanmar. A vegetatively similar fossil, which came from the same amber mines but which lacked flowers, had been previously described as a putative green alga and given the name Electrophycus. The dimensions and vegetative aspect of that taxon’s holotype specimen are identical with those of the Eophylica fossils. Four additional specimens were acquired by the senior author after the publication of Electrophycus, all of which have a single terminal flower that is either immature or essentially fully formed. Using techniques of floral dissection, high magnification microscopy, and microphotography of the better-developed flowers, we present a more detailed picture of the floral organs, especially the stamens and style, of Eophylica. These flowers differ from the holotype specimen of Eophylica and 3 of its paratypes in that they possess involucral bracts of a so-called ‘pseudanthial head,’ a structure that the authors of Eophylica had only ascribed to certain other paratype specimens of the genus.

Salpinganthium hispaniolanum gen. et sp. nov. is described as a new fossil legume from mid-Tertiary forests of Hispaniola. Arborescent legumes of tribe Detarieae previously described from these forests include Hymenaea protera and Prioria dominicana. Flowers of the new genus and species have a bilaterally symmetrical corol-la of five petals, 10 free stamens, an elongate, cylindrical hypanthium, and one or two persistent sepals, the others perhaps being deciduous. The petals are of three markedly different shapes. The pistil is exserted from the hypanthium and is densely hirsute. The bracteoles, sepals, and petals are gland-dotted, as is appropriate for members of the resin-producing Detarieae of subfamily Detarioideae.

Tropidogyne euthystyla, described here, is the fourth species of this fossil genus to have been reported from amber deposits in northern Myanmar. The species are alike in features of the calyx, the shape and venation of the inferior ovary, and the absence of petals. They differ in the number and form of the styles, the lobing of the epigynous disc, and whether the flowers are apparently bisexual or unisexual. In the one species for which several flowers are available for study, T. pentaptera, floral diameters vary from 3.5 to 5.0 mm. The present species, known only from a single flower, is the smallest in the genus, with a floral diameter of only 2 mm. It differs from the 3 previously described species in having 2 stout, erect styles bearing a terminal stigma, whereas the other species have 2 or 3 short or long, arching styles that are decurrently stigmatic along the adaxial surface.

Although partially damaged prior to its preservation in coniferous resin, the flower of Cyathitepala papillosa retains enough morphological features to justify its description as a new genus and species of fossil angiosperms. The perianth is incomplete, but there are at least 6 large outer tepals and numerous smaller, spirally arranged inner ones. The limbs of some of the larger tepals are cup-shaped and face abaxially, while the smaller inner tepals are flat or have adaxially folded margins. There is an inner series of erect, apically truncate tepals surrounding the stamens. The surfaces and margins of the tepals are densely papillate. There is a whorl of ca. 12 stamens with anthers that dehisce by two dorsally hinged valves. Nothing remains of the receptacle or pedicel of the flower, but the superior portion of the pistil is conic and bears two columnar, erect styles. The fossil is compared with three previously described fossil genera, Setitheca, Zygadelphus, and Strombothelya, which were suggested as having a possible relationship with certain families of order Laurales.

A flower preserved in 100 Ma amber from Myanmar is described here as Chainandra zeugostylus, a new genus and species of fossil angiosperms. The anthers in Chainandra are sagittate at the base and have only a short connective. They dehisce by means of a circumferential stomium, the dorsal and ventral sides of each locule forming flaps that become widely separated. The style of Chainandra is columnar and two-branched above the middle, and the fully inferior ovary bears an epigynous nectar disc but lacks well-defined ribs or veins. In Tropidogyne, Lacknociona, and Strombothelya, similar genera described earlier from the same am-ber deposits, the styles are either unbranched or are 3–5-branched to near the base, and the ovary is half-inferior to inferior, its lower portion often being dis-tinctly veined and ribbed. Morphology of the stamens and gynoecium of the three genera suggests that they are early members of the eudotyledons.

The flower described here as Valviloculus pleristaminis, a new genus and species of fossil angiosperms, was obtained from Myanmar amber deposits dating to the mid-Cretaceous period. The flower is staminate, with an ovoid, hollow floral cup. The perianth consists of 6 tepals, one of which was lost prior to preservation. Numerous helically arranged stamens are borne at the summit of the flower. The anthers are bilocular, with pollen sacs that dehisce by laterally hinged valves. The tip of the connective bears a cup-shaped appendage. The gynoecium is represented only by a cluster of vestigial styles centered among the stamens. The fossil is provisionally assigned to order Laurales, its closest affinities being with the families Monimiaceae and Atherospermataceae.

A fossil flower in mid-Cretaceous amber from Myanmar (Burma) is described as the new genus and species Phantophlebia dicycla. The perianth of the flower is composed of two 5-merous whorls of tepals, the outer tepals being smaller and more irregular in shape than the inner. All the tepals are distinctly vascularized, with few to many major veins that are connected above by an irregular network of veinlets. The flower’s 5 stamens are opposite the inner tepals, with bilocular anthers that dehisce by latrorse, oblique slits. No gynoecium can be seen beneath the air bubble covering the center of the flower. The fossil shares some characteristics with myrsinoid members of family Primulaceae.

The fossil flower described here as Thymolepis toxandra is from amber deposits in Myanmar which have been dated as ca. 100 Ma. The peri-anth consists of 12 tepals of varying size and shape, arranged in decussate pairs at the summit of an obconic floral cup. The epidermis of some of the tepals is densely papillate-secretory. The flower is bisexual, the androecium consisting of 2 stamens whose anthers are bisporangiate, hippocrepiform, and densely hirsute. The gynoecium is visible only as a bilobed stigma or as the tips of two postgenitally fused styles, the re-mainder of the pistil(s) being hidden by the perianth and floral cup. It is suggested that the fossil may be an early representative of family Monimiaceae.

A new fossil angiosperm, Dasykothon leptomiscus, is described from mid-Cretaceous amber deposits in the Hukawng Valley of northwestern Myanmar (Burma). The flower is post-anthesis except for one stamen that retains its pollen. The perianth is slightly irregular and composed of 5 ovate or lance-linear, erect or incurved sepals. The ca. 12 stamens have slender, elongate filaments and dorsifixed, bithecal, longitudinally dehiscent anthers. The superior ovary bears 2 long, curved styles. Germinating pollen grains observed on the stigmas are monoporate and have the peculiar feature of a grooved ridge encircling the grain from pole to pole. This structure is hypothesized to be an evolutionary elaboration of the meridionally syncolpate sulcus found in some members of the Atherospermataceae. The generalized floral morphology of the fossil prevents ready taxonomic assignment to a modern family.

The name Endobeuthos paleosum, previously published in this journal, was invalid due to the lack of a designation of one of the illustrations as the holotype specimen and the others as paratypes. This oversight is here corrected and the taxon name properly validated.

The flower described here as Zygadelphus aetheus gen. et sp. nov. was obtained from amber mines in Myanmar, preserved in marine sedimentary deposits dating to the mid-Cretaceous Period, ca. 99 My in age. The perianth consists of ca. 10 spirally arranged tepals that vary in size and shape. The stigmatic tips of two styles are visible, the remainder of the gynoecium being hidden from view by the crowding of stamens and perianth parts toward the center of the flower. There is a whorl of 4 stamens, the anthers of which have the feature, probably unique among angiosperms, of possessing a small but complete accessory stamen arising as an appendage on their dorsal surface. Anthers of both types of stamens are bilocular and dehisce by dorsally hinged valves. Presence of pollen in the accessory anthers indicates that they functioned in reproduction. Under the assumption that the fossil is not merely a teratological mutant in an otherwise normal-flowered species, it is here given taxonomic status as representing a peculiar type of floral development, now extinct, that existed during an earlier stage of angiosperm evolution.

The fossil flower described here is the third species of Tropidogyne to have been collected from mid-Cretaceous amber deposits in the Hukawng Valley of northwestern Myanmar. The flower of Tropidogyne lobodisca differs from the 2 previously described species, T. pikei and T. pentaptera, in lacking stamens and having a 5-lobed nectar disc covering the apex of the ovary. Its 2 slender, curved, attenuate styles are like those of T. pentaptera in being stigmatic along the adaxial surface. The new species has 5 spreading, reticulately-veined sepals, a generic character of Tropidogyne. An unusual, probably teratological, feature is the presence of 2 sepal-like staminodes on one side of the flower, inserted at the base of the nectar disc where stamens would otherwise be found. The inferior portion of the pistil is obconic, with 5 distinct veins that connect to the mid-nerves of the sepals.

Strombothelya, a new genus of fossil angiosperms from Myanmar amber deposits, is represented by 2 flowers that are here described as separate species. Flowers of Strombothelya have 5 spreading, more or less distinctly veined sepals. Petals are absent. There are 10 inwardly arching stamens and a half-inferior ovary, whose broadly conic superior portion terminates in 1 or 3 stout, columnar, apically truncate styles. The superior portion has a papillate surface that was probably nectarifer-ous. The inferior portion of the ovary in both species is obconic and 5- or 10-ribbed. The fossils are comparable in certain respects to the genus Tropidogyne, described earlier from the same amber deposits. The 3 species of Tropidogyne have flowers with 5 or 10 stamens and 2 or 3 slender, curved, acutely-tipped styles. The inferior portion of the ovary is strongly 10-ribbed, while the superior portion is flat or cushion-shaped and bears a lobed nectar-disc. Strombothelya and Tropidogyne inhabited a Cretaceous araucarian rainforest, which may have been located in the Southern Hemisphere continent of Gondwana.

Three flowers of a fossil angiosperm preserved in amber from Myanmar (Burma) are described as the new genus and species Dispariflora robertae. Although joined in a single cymose inflorescence, the flowers are variable in size and, in addition, they possess an unusual perianth in which 1 sepal is much enlarged and leaf-like, while the remaining 4 are smaller and unequal. The flowers each have 1 superior pistil with a peculiarly plumose and bristly ovary. The number of stamens is uncertain because most were lost before floral preservation, but scars on the receptacle suggest that at least 15 were present. The bithecal anthers open by longitudinal slits and basal glands may have been present on the filaments. Taken as a whole, the floral features that characterize Dispariflora suggest an affinity with members of Laurales, especially several Southern Hemisphere families allied with the Monimiaceae.

A single staminate flower preserved in mid-Cretaceous Myanmar amber is described as Setitheca lativalva gen. et sp. nov. The fossil’s affinities appear to be with Monimiaceae and allied families of order Laurales. The perianth is composed of ca. 12 spirally arranged tepals of varying size and shape. A single whorl of 10 stamens is attached to the margin of a flat central disc. There is no gynoecium. In some of the stamens, the bilocular anthers are held upright, but in the others, the filaments are arched abaxially and the anthers are reflexed. Dehiscence is extrorse via 2 lateral, dorsally-hinged valves, as also occurs in some members of Hernandiaceae. The spherical pollen appears to be inaperturate. Such features as the unisexual flowers, valvate anthers, and a perianth of numerous, spirally arranged tepals are consistent with assignment of the fossil to this order of angiosperms.

Endobeuthos paleosum gen. et sp. nov. is based on 6 flowers preserved together in a single block of mid-Cretaceous amber from Myanmar (Burma). The calyx is composed of ca. 50+ small, helically arranged sepals. The corolla consists of 5 imbricate petals forming a sheath-like structure that is usually concealed within the calyx. The petal tips are often spreading and exserted from the calyx. There are numerous stamens, each of which consists of a filament and an enlarged anther connective with a single lateral, bisporangiate theca. Dehiscence is extrorse. The tips of 3 or 4 styles are visible, indicating that the flowers are bisexual. The fossils possess unique features that prevent assignment to any modern family. However, the numerous sepals and stamens and a thickened anther connective may suggest an association of E. paleosum with the family Dilleniaceae.

In preparing the treatment of Delphinium for a future volume of Flora of Oregon, some taxonomic decisions were made that conflict with the 1997 treatment of the genus by Warnock in Flora of North America. The choice of groups to be recognized is based on the present author’s opinion that rapid evolution of Delphinium taxa occurred in the Willamette Valley following habitat disturbance caused by catastrophic flooding from the late-glacial-age Spokane Floods. Delphinium pavonaceum Ewan, D. leucophaeum Greene, and D. oreganum Howell, which are endemic to the Willamette Valley, may have evolved in the ca. 12,000 years since the floods occurred. These 3 groups are here given species rank, unlike their treatment in Flora of North America. This is in line with how the taxa are viewed by Oregon botanists concerned with the rare and endangered species of the state. Lectotypification is necessary for D. pavonaceum. A further taxonomic change is the reduction of D. basalticum M.J. Warnock to synonymy under D. glareosum Greene.

The new species described here, Artemisia estesii, belongs to the Artemisia ludoviciana Nutt. species’ group in the Pacific Northwest. It was shown by J.R. Estes (1968a, 1969) to be a diploid member of an otherwise polyploid hybrid complex, with most of its related species and subspecies occurring at the tetraploid and hexaploid levels. Artemisia estesii is recognized by its underground and emergent, over-wintering, basal shoots, which are homologs of the elongate, underground rhizomes found in other herbaceous Artemisia species. Its regularly lobed leaf blades, with usually a broad rachis, differ from subspecies of A. ludoviciana in eastern Oregon. It occupies a narrow zone of streambank vegetation along the central Deschutes River and extends eastward along the lower Crooked River. Disjunct populations are known from Wheeler County and Lake County.