Dudleya guadalupensis

A densely-leaved species of Dudleya, with the outer foliage folding over the center, giving the rosettes a rounded appearance. It has a curved flower stalk and white flowers that form a cup or "V" shape. Morphology Like most other Dudleya, this plant is a rosette-forming leaf succulent which grows rosettes on the tips of a stem, with the stem also referred to as a caudex. In this species, the caudex is thick, and elongates up to or more long, the caudex branching to form rounded clumps up to wide, of up to 80 or more rosettes. The rosettes are almost globe-shaped, wide, of 24–40 leaves, with the leaves colored a pale green, green, or white with epicuticular wax. The leaves are shaped oblong to oblanceolate, the leaf margins rounded, and the tip apiculate to acuminate. Each leaf is typically long, wide, thick, and at the base. == Taxonomy ==

Taxonomic history In 1892, Dr. Francescho Franceschi, a horticulturist from Santa Barbara, visited Guadalupe Island. He published an account of the trip and the plants he found, and among them, he reported a "Cotyledon sp." on a rock by a trail not far from the landing. The second population of Dudleya was discovered by Moran and Lindsay on Islote Afuera, a small islet off the southern coast of Guadalupe. The small islet is a volcanic cone with sheer vertical cliffs surrounded by tidal currents, but on the north side of the crater there is a small cove and a scalable slope. After failing to reach the islet with a skiff due to the dangerous conditions, Moran and Lindsay finally reached the cove with a rubber life raft, although they left their cameras behind due to the sheer danger of the landing. After overcoming the dangerous landing, Moran and Lindsay discovered what they regarded as the most interesting plant on the island, a species of Dudleya. Unlike the other plants on the northern end of the island, the plants on the islet had unusually dense green rosettes, with two different sizes of leaves. Another unusual feature was the twisting floral stem, which was present on all the plants. The peduncle is sinuously twisted, on both immature and dried inflorescences. After only one hour and a half of botanical work, Moran and Lindsay had to return to their ship, the Marviento, after the captain fired his gun to signal their return. Phylogeny Chromosome counts of the plants collected by Reid Moran on Islote Afuera and Islote Negro done by Dr. Charles H. Uhl indicate that all collections of the plant are diploid relative to the basic number for the genus, with a chromosome count of n = 17. A 1985 paper alleged that a Dudleya of this species from Guadalupe Island had a chromosome count of 2n = 102, but Moran cast doubt on the author's specimens, as the authors failed to list a herbarium record. It is likely that the authors of the 1985 paper acquired the plant as a mislabeled Dudleya greenei, which is often mistakenly sold as Dudleya guadalupensis. The hypothesis that the authors of the 1985 paper got their plant as a mislabeled Dudleya greenei is further evidenced by the fact that greenei has a chromosome count of n = 51, which corresponds to the somatic count of 2n = 102. == Distribution and habitat ==

Dudleya guadalupensis is native to Guadalupe Island and the surrounding islets. The type specimen originates from Islote Afuera (Outer Islet), collected by Reid Moran. On Islote Afuera, the plants are common from the inner slope of the crater to the upper valley. The plants there have uniformly light green foliage. On Islote Negro, plants have both green and farinose foliage, with the rosettes being less clustered and more solitary. The species is present on Islote Adentro (Islote Toro). Plants have also been spotted on Middle Rock and other islets off of the island. == Cultivation ==

Most of the examples of plants alleged to be this species in cultivation may be mislabeled. Noted Dudleya collector Paul Thomson observed that many of the plants in cultivation bear little resemble to actual D. guadalupensis plants. Reid Moran also notes that plants in the nursery trade labeled as D. guadalupensis are in fact D. greenei, a species native to the Channel Islands of California with a different chromosome count. Moran found that none of the collectors of the cultivated specimens could verify that the source was from Guadalupe Island. == See also ==