Gastrodia similis Bosser, Adansonia, sér. 3, 28: 52 (2006).
Description:
Herbe saprophyte, aphylle, à rhizomes charnus, pileux. Scapes dressés, hauts de 10-25 cm, glabres, à 3-5 nœuds, portant des gaines tubuleuses longues de 4-6 mm, tronquées et munies d’une courte pointe au sommet. Inflorescences terminales, en racèmes (1-)3-10-flores, à axe long de 1-3,5 cm; bractées ovales, sub-aiguës, longues de 3-5 mm. Pédicelles grêles, cylindriques, longs de 4-6 mm. Fleurs blanc grisâtre à beige. Sépales charnus, longs de 10-14 mm, le sépale médian soudé aux sépales latéraux sur les 3/4 de sa longueur, sépales latéraux soudés antérieurement entre eux sur environ 1/3 de leur longueur, les sépales formant un tube gibbeux à la base du côté antérieur et à lobes largement triangulaires, obtus, cucullés et à carène arrondie sur le dos, verruqueuse sur les sépales latéraux. Pétales un peu charnus, largement ovales, obtus, un peu concaves, 4-5 x 4-5 mm, insérés au sommet du tube sépalaire dans les sinus entre le sépale médian et les sépales latéraux. Labelle dressé contre la colonne et inséré à sa base, charnu, largement ovale, 6-7 x 3,5-3,7 mm, à acumen court et large, arrondi au sommet, base tronquée, onguiculée, onglet libre, plat et court, portant 2 callosités charnues ± en forme de croissant ; marges latérales un peu relevées, papilleuses, face supérieure transversalement un peu ridée sur la partie basale (ce caractère peu visible) et portant vers le sommet un épaississement charnu médian prolongé sur la base de l’acumen et bilobulé au sommet, face inférieure arrondie, canaliculée le long de la nervure médiane. Colonne charnue, dressée, haute de 5-6 mm, rétrécie à la base munie d’un pied court, face antérieure plane à marges largement arrondies. Stigmate ovale, situé à la base de la colonne. Rostelle tronqué. Anthère subcirculaire, de ± 1,5 mm de diamètre, largement arrondie à l’avant, à connectif épaissi vers l’arrière ; pollinies 2, granuleuses, portées par une viscidie commune. Ovaire trigone, obconi-que, long de ± 4 mm. Capsule ovoïde, 2-2,5 x 0,8-1 cm ; pédicelle accrescent, atteignant 30-35 cm de longueur.
Habitat:
Endémique ; récoltée pour la première fois, en fruits, par T. Cadet à St. Philippe en 1968. Plante du sous-bois de la forêt humide de basse altitude (0-500 m). Peu commune et n’apparaissant peut-être pas tous les ans.
Notes:
Gastrodia similis Bosser is a small terrestrial orchid endemic to the Southeast area of LaRéunion (PICOT & LUCAS, 2016, SZELENGOWICZ & TAMON, 2013, BERNET, 2010) .Aphyline and non-chlorophyllian, this species is called mycoheterotrophic because it feeds on sugars that it extracts from symbiotic fungi from its roots, thus allowing the growth of its underground rhizome and its flowering (MARTOS et al., 2009).
Distribution:
Réunion
References:
BERNET, P., 2010. – Les orchidées de La Réunion.Naturae Amici éditions; Adansonia, sér. 3, 28: 52 (2006).

Images:
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Habitat/In situ

Photograph ©Frederic Henze. Image used with kind permission.

Gastrodia africana Kraenzl., Bot. Jahrb. Syst. 28: 179 (1900).
Type:Cameroon, between Love and Ndiva, Dusén 397 (holotype B†; isotype S!).
Description:
Leafless achlorophyllose erect herb, up to 3 – 4 cm tall, rhizome tuberous, elongated up to 4.5 – 20 × 8.8 – 1.2 cm. Scale leaves 4 – 8, 8 – 12 mm long, truncate with abruptly pointed apex. Inflorescence lax, up to 1.5 – 2 cm long, with 3 – 8 flowers, bracts brown, 6 – 8 mm long. Flowers campanulate, green, up to 12 mm long, sepals and petals fused; pedicel 6 mm long; ovary 3 – 4 mm long. Dorsal sepal 8 – 9 × 4 – 5 mm, ovate-obtuse; lateral sepals 10 – 12 × 5 mm, ovate-lanceolate. Petals 7 – 7.5 × 1.5 – 2 mm, ovate. Lip 3-lobed, ovate, with 2 white calli at base, basal part 4 – 4.5 × 4 – 5 mm, thickened at centre, with 2 glandular calli near the base of the midlobe, midlobe oblong-ovate, obtuse, 2.5 × 2 mm. Column 5.5 mm long. Fruit with pedicel elongating up to 2 cm long, capsule up to 2.5 cm long.
Habitat:
In submontane forest with Allanblackia gabonensis (formerly A. monticola), Carapa grandiflora and Cola sp.; 1100 – 1200 m.
Notes:
Gastrodia africana Kraenzl. was considered locally endemic to the Mt Cameroon area where it is considered to be possibly extinct (Cable & Cheek 1998). It was discovered by Dusén (Dusén 397) on Mt Cameroon between "Love und Ndive" in the month of April. These localities are possibly those known today as Lobe and Ndibe, in a major plantation area immediately to the north of Mt Cameroon (Cable & Cheek 1998). The holotype is believed to have been destroyed in Berlin but an isotype survives in S. A collection from Mt Kala near Yaoundé (Letouzey 9509) was referred to this species by Sanford (see Szlachetko & Olszewski 2001), but this assignment is debatable (Cable & Cheek 1998).
Distribution:
SW. Cameroon

Gastrodia ballii P.J.Cribb & Browning, Kew Bull. 65: 317 (2010).
Description:
A holomycotrophic herb growing from a subterranean fusiform rhizome, 30 – 40 × 9 – 14 mm, each rhizome arising from the apex of the previous one, with a narrow stalk 10mmlong; roots fine, 40 – 50 mmlong, at base of rhizome only. Inflorescence 40 – 60 mm tall, densely racemose; peduncle whitish chocolate brown; leaf scales 3 – 4, appressed, papery, 7 mm long, claret-coloured; fertile bracts ovate, acute, 6 × 2.3 – 3 mm. Flowers resupinate, 1 – 5, borne at right angles to the rachis, campanulate, somewhat rugulose on the outer surface of the sepals, liver-coloured to grey-brown with pale fleshcoloured petals and a yellow green lip with an apricot tip; pedicel and ovary 11 mm long, pedicel lengthening after fertilisation; ovary subtriangular in cross-section, pustulate. Sepals subsimilar, fused into a tube for three-quarters of their length, 12 × 6.5 mm. Petals borne on the sepals where the sepals split, broadly ovate, obtuse or rounded, 2 mm long and broad, erose. Lip fleshy, porrect, ovate, rounded and slightly decurved at apex, 4.5 – 5 × 3 mm; callus somewhat Vshaped, of two incurved ridges united at the front. Column clavate, 7 mm long, with two acute apical stelidia; foot incurved, fused to perianth at the base, with two apical cephaloid tubercular processes. Fruit erect, 33 – 35 mm long, the elongated stalk 10 – 50 cm tall, olive-brown.
Habitat:
In deep leaf mould near rocks in riverine forest of Khaya/Newtonia and Craibia/Newtonia forest in deep shade; 700 – 800 m.
Notes:
This species is undoubtedly close to Gastrodia rwandensis but differs in its flower colour, tiny petals and lip which is ovate and very obscurely 3-lobed and has and inverted V-shaped callus. It has been found in a small area on the Mozambique/Zimbabwe border and also in southern Malawi. Because of its ephemeral nature, being seen above the ground only when in flower and fruit, it might be expected to be more widespread and should be searched for in appropriate habitats.
Distribution:
S. Malawi, NE. Zimbabwe, WC. Mozambique
Images:
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Botanical Drawing / Herbarium

Photograph copyright Swiss Orchid Foundation at the Herbarium Jany Renz Image used with kind permission.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gastrodia madagascariensis Schltr. ex H.Perrier, Repert. Spec. Nov. Regni Veg. Beih. 33: 123 (1924).
Homotypic Synonyms:

Didymoplexis madagascariensis (Schltr. ex H.Perrier) Summerh., Kew Bull. 8: 131 (1953).
Description:

Herbaceous plants, 20-40 cm tall, entirely white, except for the base of the scape and the capsules which are brownish; rhizome thick, blackish, horizontal, 3-5 cm long, covered with reddish-brown hairs, scape 11-18 cm tall, 2-6 mm in diameter, with 3-4 internodes and as many short, thin sheaths, raceme 4- lowered; rachis 3-10 cm long; bracts lanceolate-acute, 6-8 mm long. Flowers ?; pedicels fructiferous, s much as 30-40 cm long and 2-3 mm in diameter. Capsule oblong (25 x 5 mm).
Habitat:

Terrestrial; in eastern forests, from 2000 m alt.; flowering in September.
Distribution:

NE. Madagascar