What kind of succulent plant is Dudleya gnoma?

Dudleya gnoma (scientific name: Dudleya gnoma S.W.McCabe) is a succulent plant in the genus Dudleya of the family Crassulaceae, native to California, USA.

Dudleya gnoma

Morphological characteristics:

Stems 5 - 26 long, (1.5-) 12 - 20 mm wide. Rosette diameter 8-51 mm, leaves 8-19, readily forming clusters, perennial plants cushion-forming, up to 57 heads. Leaves triangular to triangular-ovate, (6-) 9 -25 mm long, 5 - 13 mm wide, acute, covered with a thick white farina. In environments with sufficient sunlight and a certain temperature difference, the front part of the leaf turns red. Inflorescence covered with white farina, usually with 2 (-5) unbranched or once-branched scorpioid cymes, spreading at first, later horizontal or recurved, 2.5 - 12.9 cm long, bracts from pale deep red at first, gradually turning purplish red as they wither. Pedicels upright, 1 - 3 mm long. Sepals triangular, acute, 3.5 - 4 mm long, 2 - 3 mm wide, tips wine-red or yellow-green, covered with white powder. Petals twisted in bud, upright when open, elliptical, apex occasionally recurved, 8 - 9(-11) mm long, 3 mm wide, pale yellow to bright yellow, sometimes orange-yellow, corolla tube 1-2 mm.

Dudleya gnoma

Growth habits:

Dudleya gnoma prefers a warm, dry environment with plenty of sunlight. It is not cold-hardy, tolerates partial shade and drought, and fears waterlogging and intense direct sun. In summer, when temperatures are high and water is scarce, it enters a semi-dormant state.

Species distinction:

The scientific name of Dudleya gnoma is often misreported online as "Dudleya greenei". However, the leaves of Dudleya greenei are actually much longer than those of the Dudleya gnoma discussed in this entry, and its overall plant form is also larger.

Dudleya gnoma

The correct scientific name of the plant called "Dudleya gnoma" domestically should be Dudleya gnoma. The misreporting and confusion with Dudleya greenei may be because Dudleya gnoma has two synonyms: "Dudleya greenei fa. nana (Moran, 1951)" and "Dudleya greenei cv. White Sprite", and both synonyms contain the word "greenei", which led to the name being misreported as Dudleya greenei when introduced domestically, causing confusion. Therefore, the "maru-leaf Dudleya gnoma" and "common Dudleya gnoma" sold in China are both Dudleya gnoma, and Dudleya greenei is actually very rare in the domestic succulent market.