B
Identification Criteria for Plant Remains
Karen R. Adams
Contents
Amelanchier/Peraphyllum-type
Artemisia tridentata-type
Artemisia-type
Atriplex-type
Capparaceae-type
Cercocarpus/Artemisia-type
Cercocarpus-type
Cheno-am
Chrysothamnus-type
Cycloloma atriplicifolium-type
Cyperaceae-type
Echinocereus-type
Ephedra-type
Euphorbia glyptosperma-type
Fraxinus anomala-type
Gramineae
Juniperus osteosperma-type
Juniperus-type
Malvaceae-type
Mentzelia albicaulis-type
Monocotyledon-type, including Yucca-type
Nicotiana attenuata-type
Opuntia-type (prickly pear)
Phaseolus vulgaris-type
Physalis longifolia-type
Pinus edulis-type
Pinus-type
Pinus ponderosa-type
Plantago-type
Populus/Salix-type
Portulaca retusa-type
Purshia-type
Quercus-type
Rhus aromatica-type
Scirpus-type
Stipa hymenoides-type
Termite
Triticum-type
Unknown
Zea mays
The following observations and criteria were used in the identification of plant remains from the tested sites, including wood charcoal. Taxa are listed alphabetically.
Amelanchier/Peraphyllum-type
Charcoal. Vessels are present, solitary, evenly and closely spaced throughout ring, abundant, and minute; vessels are larger in earlywood, becoming smaller in latewood; rays are one to two cells wide.
Artemisia tridentata-type
Flower bud. These structures are tear-drop-shaped, measuring 1.3 mm in length by 0.8 mm in width at the apex. Most are swollen considerably, with interior contents extruding out in some cases. Some have bractlike ancillary parts attached to their bases. The surface is rough and generally devoid of features. These items compare well in shape and attached parts to modern developing Artemisia tridentata flower buds observed in the Cortez area in late September/early October. However, the prehistoric specimens are larger than modern flower buds, which may be partly due to the expanding effects of steam trapped in an immature flower bud.
Leaf. Big sagebrush leaves are generally long (up to 1.2 cm) and narrow (between 1.0 and 3.0 mm) structures with three lobes at the distal end. Although such leaves are also common to locally available Purshia tridentata shrubs, the ancient specimens more closely matched Artemisia tridentata leaves in degree of lobing, slight inrolling of edges, and lack of leaf tip prickles.
Artemisia-type
Charcoal. Vessels are present, in irregular aggregates with a flamelike dendritic arrangement; rays are obvious, up to 3+ cells wide; a distinct band of cork tissue initiates each growth ring; rings often fracture along cork tissue, causing "ring shake" (a tendency to break at annual ring boundaries); many lenticular pores are visible in tangential view.
Atriplex-type
Charcoal. Vessels are present; rays are absent or indistinguishable; rings display a distinct ripplelike banding pattern made up of a series of alternating arcs of vessel and nonvessel areas.
Capparaceae-type
Seed. The ovate seeds measure 2.6 by 1.9 mm and have the strongly curved embryo with a "hooked beak" found in members of the beeweed/caper family, such as Cleome and Polanisia.
Cercocarpus/Artemisia-type
Axillary bud. These specimens are round, pithy-centered cylinders of variable length, covered with a number of overlapping bracts attached at intervals. Occasionally the unbroken distal end appears pointed. Axillary buds of locally available Cercocarpus and Artemisia buds are similar in appearance to these ancient specimens.
Cercocarpus-type
Charcoal. Vessels are present, solitary, rather widely spaced; vessel size is variable throughout ring; rays are one to two cells wide and abundant; ring boundaries are faint, demarcated by widely spaced earlywood vessels.
Cheno-am
Seed. Cheno-ams are compressed, generally circular seeds with a lenticular or plano-convex cross section. They vary in size from less than 1 mm in diameter up to 1.5+ mm and when broken open display an embryo curved in a ring around the perimeter of the seed. Surface texture is usually smooth or obliterated by charring.
Chrysothamnus-type
Charcoal. Vessels are present; larger earlywood vessels grade into smaller latewood vessels; vessels vary in geometric form (few are circular); continuity of annual band is interrupted by obvious rays 3+ cells wide; the pith has a different cell arrangement; occasionally lenticular pores are visible in tangential view. Chrysothamnus is similar to Artemisia wood, but lacks the cork tissue and flamelike arrangement of the vessels of Artemisia.
Cycloloma atriplicifolium-type
Seed. Seeds are circular-lenticular in face view, rounded on the margins, and have an embryo that curls completely around the perimeter of the seed giving an almost heart-shaped appearance. Evidence of an attached, flattened calyx is still preserved on a few specimens. Seeds measure 1.6-1.8 mm in diameter. The heart shape and larger size distinguish Cycloloma seeds from the general category of cheno-am remains.
Cyperaceae-type
Achene. The Cyperaceae-type achenes are ovate in outline, triangular in cross section, and measure 1.5-2.0 mm in length and 0.7-1.1 mm in width. Two specimens have a raised area at the apex that might be the base of a former style; others have broken off at this point. The surface texture is rough, with some parallel striations visible beneath encrusted material. Difficulties in distinguishing triangular achenes of certain southwestern sedge genera such as Scirpus and Carex (Martin and Barkley 1961:138) require that a conservative identification be attached to five charred achenes recovered from the lower ash of a roasting pit at Troy's Tower (5MT3951). The plano-convex achenes of locally available Scirpus acutus are no match for the charred specimens.
Echinocereus-type
Seed. Seed is a compressed oval, with a cavity near the base and a surface coarsely roughened by rounded protuberances. The seed measures approximately 2 mm in its longest dimension. This seed type compares well to modern Echinocereus fendleri-type seeds in the area.
Ephedra-type
Charcoal. Vessels are present, minute, and concentrated in earlywood; rays are obvious, up to 3+ cells wide; rings are faint.
Euphorbia glyptosperma-type
Seed. Quadrangular-ovoid seed, with a distinct longitudinal line and a few cross ridges. Seed type measures just over 1.0 mm in length and 0.50 mm in width.
Fraxinus anomala-type
Charcoal. Vessels are present; clearly ring porous; large vessels in earlywood, with many smaller vessels in later wood which seems mostly composed of dense background cells; rays are hard to see, very thin, and numerous. In oblique lighting, several bands of vessels are apparent in latewood.
Gramineae
Caryopsis #1. The grain (PD 144, PL 1)(1) measures 2.3 mm in length by 1 mm in width; the embryo depression occupies 0.3 mm of the length, placing the grain in a group of grasses known as the Festucoideae (Pooideae) (Gould and Shaw 1983:99). The grain is swollen and the non-embryo (ventral) side is somewhat distorted, making it difficult to determine if a groove was formerly present. Parallel striations barely visible on the embryo (dorsal) side may represent nerves or constrictions imposed by a tightly fitting bract.
Caryopsis #2. Two complete long and narrow grains (PD 63, PL 4) are rather large specimens, measuring 3.5 mm in length and 1 mm in width. The relative proportion of the embryo (at 1.2 mm in length) places the grains in the same group of grasses (Festucoideae/Pooideae) described above. In shape, the grains are slightly rounded on the embryo (dorsal) side. One grain is flat and the other slightly sunken on the palea side, where both have an obvious central nerve running down the center and a slightly notched apex. Parts of the palea are actually still attached to the best preserved grain. These grains do not have the sharply keeled V-shape of Bromus species; other local grass possibilities that must be explored include Elymus, Agropyron, Sitanion, and Festuca.
Juniperus osteosperma-type
Fruit, seed. Specimens have a thick, woody wall with a single stony seed inside. They can measure up to 5.8 mm in length and 4.5 mm in width. Although these characteristics are perhaps more typical of Juniperus monosperma (Kearney and Peebles 1960:59), the author has observed some modern fruit of Juniperus osteosperma to have both small size and single-seed characteristics. The name Juniperus osteosperma has been applied due to the common occurrence of this species in the region today; however, the possibility exists that the fruit and seeds represent Juniperus monosperma.
Twig. Twigs are short (< 5 mm) segments of stems with whorls of two to three overlapping triangular leaves. At 30× magnification, minute teeth are often visible along the margin of each leaf, suggesting that the twigs derive from either Juniperus osteosperma or Juniperus monosperma. Of these two species, the former is presently common in the region.
Juniperus-type
Charcoal. No vessels are present; resin canals are absent, but occasionally trauma-induced resin ducts or holes that mimic resin canals are present; latewood zone is narrow to very narrow; earlywood zone is wide, occupying most of the ring; boundary between the latewood of one ring and the earlywood of the next ring is sharply demarcated.
Malvaceae-type
Seed. Seeds are compressed and reniform, each with a notch near the point of attachment. The margin opposite the point of attachment is broad and composed of two ridges with an intervening shallow trough or groove. The seeds vary in size, up to 2 mm in longest dimension.
Mentzelia albicaulis-type
Seed. Seeds are irregularly angled, with numerous individual facets present and a noticeably beaded appearance to the surface. They are small, ranging between 0.65 and 1.00 mm in longest dimension.
Monocotyledon-type, including Yucca-type
Tissue. Monocotyledon tissue is distinguished by scattered vascular bundles in a background matrix; when discernible, the vascular bundles are arranged in parallel rows. This tissue may represent any of a number of Monocotyledons, such as grasses (including Zea mays) and Yucca.
Nicotiana attenuata-type
Seed. Tobacco seeds are reniform or angular-reniform and have a distinctive "wavy-walled" appearance. They can vary in length from 0.4 to 1.3 mm. The tested site seed is badly degraded and cannot be measured accurately. It has been identified as Nicotiana attenuata-type on the basis of the presence of this species in the region.
Opuntia-type (prickly pear)
Seed. Prickly pear-type seeds are basically circular in shape, flattened in cross section, and have a distinct groove parallel to the margin around the seed perimeter. They range from 3.2 to 4.4 mm in diameter, averaging 3.8 mm (N = 13).
Phaseolus vulgaris-type
Cotyledon. The large size of these legume seed halves (e.g., 12.8 mm long, 6.4 mm wide, and 3.2 mm thick) and their reniform shape combine to suggest that they represent domesticated common beans (Kaplan 1956:205).
Physalis longifolia-type
Seed. Physalis seeds are flat and oval to elliptical in face view. Key characteristics include an obscure notch with a marginal scar along one edge and a surface texture that is cellular-reticulate. They average 1.5 by 1.2 mm in size.
Pinus edulis-type
Needle fragment. The key identifying characteristic of pinyon needles is their channeled shape, which is semi-terete in cross section, suggestive of a two-needled pine.
Pinus-type
Bark scale. Bark scales are flat and varied in size, though they are not generally larger than 1 cm in the longest dimension. The specimens are contoured, with a surface that is thickened toward the center and slopes toward the edges. Sometimes minute round holes are present, suggestive of insect activity.
Charcoal. Recognized by a lack of vessels and the presence of resin canals throughout the ring; the latewood zone is usually wide when compared with Juniperus-type wood; the boundary between the latewood of one ring and the earlywood of the next ring is distinct; the transition from earlywood to latewood is abrupt; small lenticular pores are sometimes visible in tangential view. Pinus-type wood could represent Pinus, Picea, or Pseudotsuga. Resin duct criteria that distinguish these major genera (Minnis 1987:125) were difficult to see at the magnifications employed in this study.
Cone scale. Cone scale is oblong, flattened along part of its length, and has both an umbo (a raised area on the dorsal surface of the scale) and an apophysis (swollen part of the scale surrounding the umbo). Since the umbo is broken, it is not clear whether the cone scale represents pinyon (umbo lacks a sharp prickle) or Ponderosa pine (umbo has a sharp prickle).
Pinus ponderosa-type
Cone scale. See definition of Pinus-type cone scale (above). The umbo of Pinus Ponderosa-type cone scale has a sharp prickle.
Plantago-type
Seed. The seed is ovoid, with one convex surface and one flat surface. The flat surface often has a thickened rim around the edge, highlighted in burned specimens.
Populus/Salix-type
Charcoal. Vessels are present, abundant, and closely spaced; the first row of solitary earlywood vessels makes a noticeable ring; wood is semi-ring porous (that is, there is a gradual transition in size from larger earlywood vessels to smaller latewood vessels); rays are one to two cells wide and abundant; the number of vessels between any two rays ranges from one to three.
Portulaca retusa-type
Seed. These minute seeds are generally less than 1 mm in diameter, circular in cross section, and characterized by concentric rows of low, knobby tubercles visible on the surface at 50× magnification.
Purshia-type
Charcoal. Vessels are present and solitary; a ring of closely spaced vessels is present in the earlywood at the clearly demarcated ring boundary; vessels become minute and widely spaced in latewood; rays are one to two cells wide; rings are occasionally lobate in form.
Quercus-type
Charcoal. Vessels are present; wood is distinctly ring porous, with vessels in earlywood noticeably larger than those in latewood; there is a somewhat erratic distribution of clusters of smaller vessels in dense latewood; large rays are visible, except near center of stem; occasionally smaller rays are visible.
Rhus aromatica-type
Seed. The ovoid whole seeds (PD 67, FS 12) are compressed and have a characteristic lens-shaped opening (hilum) along the margin with longitudinal lines radiating away from it. Although one seed fragment (PD 166, FS 36) is missing the diagnostic hilum area, in cross section the seed coat wall has the two-layered appearance of Rhus (United States Department of Agriculture 1974:716).
Scirpus-type
Achene. Specimens are ovate in outline and triangular in cross section. A blunt or pointed style base provides the criterion needed to recognize Scirpus from other members of the Cyperaceae.
Stipa hymenoides-type
Floret. Florets are shaped like light bulbs, bulbous at the proximal end and pointed at the distal end. They can measure up to 4.0 mm in length by 1.5 mm in width.
Termite
Fecal pellet. These items are oblong, hexagonal, and generally bullet-shaped (Adams 1984). They are very small, measuring less than 1 mm in length.
Triticum-type
Caryopsis. The specimen measures 1.3 mm long by 0.8 mm wide at its widest point directly above the embryo. In lateral view it displays a distinct dorsal ridge, a sharply angled embryo that occupies less than one-third of the length of the specimen, and a distinct ventral groove or furrow.
Unknown
Seed Type 1. A charred seed of unknown taxonomic affiliation preserved in the floor ash of the tower at 5MT3951 (Troy's Tower). This rather large seed, measuring 3.3 mm in length and 1.7 mm in width, is shaped like a teardrop, widest at the apex and gradually tapering to the base. A barely discernible groove appears to run along the long axis in one location. The roughened exterior holds no clues to identification.
Zea mays
Cob fragment. A cob is the female reproductive structure of corn that holds the rows of "kernels" or grains. A fragment is a broken piece of cob consisting of more than one cupule (see below), but is not complete around the circumference.
Cob segment. A segment is a broken piece of cob of some length that is complete around the circumference (hence can be evaluated for the number of rows it contains), but is missing both the apex and the shank ends.
Cupule. A cupule is a durable part of a cob which often preserves after all other parts have degraded. A cupule is a cuplike structure which holds two spikelets, and each spikelet in turn holds a single corn kernel or grain.
Kernel. A kernel is the caryopsis (fruit), sometimes called the "grain" of corn.
Stalk segment. A stalk segment, also called the shank, is a piece of the stem from below the cob. Stalk segments are round to elliptical in cross section, complete around their circumference, and in cross section are solid with scattered vascular bundles.
Stalk fragment. A stalk fragment is a broken piece of stem, incomplete around the circumference.
1. PD, FS, and PL numbers are part of the Crow Canyon provenience and laboratory tracking system.