Cenchrus echinatus is an annual grass with decumbent culms at the base and grows to a height of 25 to 70 cm. The stems are profusely branched, compressed, and usually geniculate (bent at the nodes), often reddish near the nodes and lower portions. They are scabrous for several centimeters below the panicle, though otherwise glabrous. The leaves consist of a sheath 4 to 7 cm long, which is compressed and either glabrous or slightly roughened (scaberulous), with a conspicuous whitish collar. The ligule is densely ciliate and about 1 mm long. Leaf blades are flat, measuring 5 to 18 cm long and 3 to 9 mm wide. They are striate with a prominent midrib; the adaxial (upper) surface is rough (scabrous) and may be sparsely hairy at the base, while the abaxial (lower) surface is either glabrous or scabrous near the apex. The inflorescence is a 3 to 7-cm-long spikelike panicle with a zigzag rachis bearing scabrous angles. The burs, readily deciduous and broadly ovoid, measure 4 to 7 mm in length and are as wide or wider. Each bur has an obconical receptacle (1–2 mm long) that is softly hairy (tomentulose). The bur’s lobes are deeply cleft and covered in short tomentulose hairs. The outer bristles are 2–3 mm long and retrorsely scabrous, while the inner bristles are flattened, short-pilose at the base, and scabrous toward the tip. Each bur contains 3 to 5 spikelets (pictured), each 4 to 6 mm long. The first glume is membranous, scalelike, indistinctly 1-veined, and 1–1.5 mm long. The second glume is also membranous, 4–4.5 mm long, 3-veined, and minutely scaberulous with an acute apex. The sterile lemma measures 4.5–6 mm in length, is 5-veined, and has an acuminate apex; the sterile palea is about the same length, 2-veined, submembranous, glabrous, and with an attenuate tip. The fertile lemma is around 5 mm long, 5-veined with scaberulous veins near the apex, and ends in an attenuate tip. The fertile palea mirrors the lemma in length and shape, being 2-veined, glabrous, and acuminate. The fruit is a caryopsis that is broadly ovate, typically flattened on the ventral side and rounded dorsally, and measures 3 to 4 mm in length.
Bean-shaped (Reniform): Resembling the shape of a kidney or bean.
Square or Oblong: Angular shape with all sides more or less equal or longer than wide.
Triangular: Three-sided shape, broadest below the middle.
Elliptic: Rounded at both ends. shaped like an ellipse or oval.
Ovate or Obovate: egg-shaped, broader at one end.
Linear: Extremely long and narrow, with sides usually parallel.
Round: Appears circular, with length and width roughly the same.
Cardioid (Heart-Shaped): One edge has a prominent double curve into two lobes.
Cylindrical: A cylinder with parallel sides and a circular cross-section.
Discoid: Resembling a disc or plate with two relatively flat surfaces.
Fusiform: Spindle-shaped, tapering at both ends.
Globose: Spherical.
Lenticular: Resembling a lens with two convex surfaces.
Ovoid: Egg-shaped.
Plano-convex: Having a flat ventral (planar) surface and a curved dorsal (convex) surface.
Polygonal: Having more than three flat faces meeting at angles.
Sectoroid: Resembling a segment of an orange with two relatively flat faces and one curved face.
Subglobose/ellipsoid: Inflated shape but less than spherical.
Trigonous: Having three faces that meet at a distinct angle; triangular in cross-section.
Endangered species (E) are species that are so rare they’re in danger of becoming extinct.
Threatened species (T) are species that are likely to become endangered within the foreseeable future throughout all or a significant portion of their range.
Species of Concern (SOC) are species about which there are some concerns regarding status and threats, but insufficient information is available to list the species under the Endangered Species Act (ESA).
Plant Extinction Prevention (PEP) is a state status for rare plants that focuses its efforts on species that have fewer than 50 remaining wild individuals.
Orthodox seeds (desiccation-tolerant): can be dried to an internal seed moisture of less than 12% water and stored at freezing temperatures.
Intermediate seeds (temperature-sensitive) tend to age faster than orthodox seeds and may have only a 5-year lifespan when stored at -20°C. They are recommended for storage at 5°C.
Recalcitrant seeds (desiccation-sensitive): cannot be stored in a conventional freezer as they cannot survive after drying and/or freezing at -20°C. They are recommended for cryopreservation storage.