Sayeria alexandrae

The following article was written for the Orchid Species Bulletin published by the Orchid Species Society, which is based in Brisbane, Queensland in September 2003, and updated in April 2021.
Bear in mind that any cultivation notes refer to the subtropical conditions of Southern Queensland, Australia.

Sayeria alexandrae (Schltr.) Rauschert was first described by Rudolf Schlechter as Dendrobium alexandrae Schltr. in Repertorium Specierum Novarum Regni Vegetabilis Beihefte in 1912. Schlechter named it in honour of his wife, Alexandra Sobennikoff, daughter of a Russian Tea Merchant, who helped him compile his famous work, Die Orchideen von Deutsch-Neu-Guinea.

Morphological and molecular studies show that the generic limits of Dendrobium need to be reviewed. Based upon these studies, Mark Clements and David Jones resurrected Fritz Kraenzlin’s genus Sayeria in The Orchadian in 2002. Genera Orchidacearum 6 (2014), and the Plants of the World Online [POWO] have not been consistent with classification of Orchidaceae. It ignores morphological characters, and treats the genus Dendrobium as a highly variable genus.

I prefer a consistent taxonomic treatment of Orchidaceae, and recognise Sayeria Kraenzl. as distinct from Dendrobium. Sayeria includes the majority of the species that have been previously included in Dendrobium section Latouria. Stephan Rauschert transferred many of those species to Sayeria, including Den. alexandrae, in Feddes, Repertorium Specierum Novarum, Beihefte in 1983. Despite the similarity of the flowers of some species, Mark Clements (pers. email) says that Den. spectabile Lour., the type species of Latouria, is unlike the other species that have been traditionally included in that section. Sayeria are unable to hybridise with Dendrobium.

Sayeria alexandrae was considered to be lost for over 70 years after its first publication. Thankfully since its rediscovery by Phil Spence, seedlings are now in cultivation.

Say. alexandrae is a robust, sympodial, epiphytic plant, which produces spindle-shaped, longitudinally grooved pseudobulbs that are 27-55 cm tall, and 1-2 cm in diameter. At the apex of the pseudobulbs are 3-4 leathery, elliptic, bluish-green leaves, which are 11-16 cm long, and 3.5-5.5 cm broad. Racemes that are generally erect are produced from nodes towards the apex of the matured pseudobulbs. Each pseudobulb produces further racemes over several consecutive seasons.

The racemes of Say. alexandrae are up to 25 cm long, and, bear 3-7 large, showy flowers, which are 5-8 (-10) cm across. The flowers have yellowish sepals and petals, which are finely spotted with dull red on the outer surface. Its large lip is cream-yellow with a prominent greenish midlobe, which is marked with violet-red, to brownish violet veins and spots. The side lobes are veined with violet-red, and the column and callus are white. The blooms produce a faint honey-like scent during the day. Long-lived, the lowers last for 6 weeks.

Endemic to New Guinea, Say. alexandrae is found near Gobi in the Waria Valley at around 900-1,100 m altitude. It is an intermediate-growing species that Phil Spence (1996) has found it to do best with a minimum of 14 ^⁰C with a lot of air movement. Phil says that once the plant is established it will grow quickly into a specimen plant. He’s also found that regular back-cutting will help it to develop multiple leads growths, and become a large plant. Say. alexandrae also requires a well-drained medium, regular water, and high humidity while it is actively growing. Howard Wood (2006) says that this species does not need a dry season, so plants should not be allowed to remain dry for long periods.

References:                                    

Baker, M.L. & C.O. Baker. (1996) Orchid Species Culture – Dendrobium. Timber Press, Portland, Oregon.

Clements, M.A. & D.L.Jones. (2002) “Nomenclatural Changes in the Dendrobieae (Orchidaceae) 1: The Australasian Region.” Orchadian 13 (11): 484-497.

Cribb, P. (1983) “A revision of Dendrobium sect. Latouria (Orchidaceae).” Kew Bulletin reprint, 38 (2): 229-306.

Ossenbach, C. (2009) “Orchids and Orchidology in Central America: 500 years of History.” Lankesteriana, 9 (12): 1-268.

Rudkin, R. (2000) “Orchids and Rudolf Schlechter.” The Orchadian, 13 (4): 182-184.

Spence, P. (1996) “Notes on Dendrobium alexandrae Schltr.” The Orchadian, 12 (1): 19-22.

Wood, H.P. (2006) The Dendrobiums. A.R.G. Gantner Verlag K.G., Liechtenstein.