Hibiscus arnottianus subsp. immaculatus can grow as shrubs or small trees, reaching heights up to 8 to 10 meters. The mature stems of this plant are glabrous to glabrate, while the younger stems, petioles, and calyces are adorned with copious yellowish stellate pubescence. Its leaves are simple and alternate, with ovate-elliptic to broadly ovate blades 4 to 30 cm long and 2 to 25 cm wide. It features an acute to subacuminate apex and an obtuse subcordate or cuneate base. The upper surfaces of the leaves are glabrous or glabrate, whereas the lower surfaces range from glabrate to densely pubescent, with the blades being coriaceous and margins usually deeply crenate. The flowers are solitary and located near the ends of branches, supported by stout pedicels. The calyx is tubular, 5-lobed, or 5-parted, sometimes featuring yellowish stellate pubescence. The corolla is white, occasionally with a pink tinge on the abaxial side, and flares out from the base, where it is adnate to the staminal column. The stamens form an exserted staminal column, with filaments arising in the upper part. The ovary is superior, leading to fruit that are loculicidally dehiscent capsules enclosed by the calyx, and the seeds are angular-reniform or rounded-reniform, yellowish-brown tomentose. It primarily occurs in mesic to wet forests at elevations ranging from 300 – 800 meters.
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.