Taxonomic treatment
Geodorum laxiflorum Griff., Calcutta J. Nat. Hist. 5: 356, t. 24. 1845; Hook. f., Fl. Brit. India 6: 18. 1890; Seidenf., Opera Bot. 72: 51. 1983; S. Misra, Orch. Orissa: 560. 2004; Misra, Orch. Orissa Handb.: 180. 2014; M.R. Bhatt et al. Richardiana 15: 335. 2015; Veeranjaneyulu et al. Res. Ex. Inter. Multidis. Res. J. 7(7): 38. 2017; A.R. Bhoyar & al., J. Threat. Taxa 14(2): 20689. 2022 – Lectotype (designated here): INDIA. ‘HBC’, Griffith s.n. (CAL barcode CAL0000055002!, Fig. 2a; collector’s name not mentioned on label, but identified with handwriting).
Syntype. – Assam, Jenkins s.n. (CAL barcode CAL0000086400!, Fig. 2b).
≡ Eulophia diffusiflora M.W. Chase, Kumar & Schuit., Phytotaxa 49(1): 52. 2021, syn. nov.
Description. Terrestrial herbs, 20–40 cm long or rarely up to 50 cm. Corms or pseudobulbs 2–4 cm long, 1–2 cm thick, oblique, ovoid, slightly compressed, greenish brown, with scars of fallen leaves, borne on a short rhizome. Roots few to many, 2–12 cm long, vermiform. Pseudostem 6–10 cm long, enclosed by 3–4 foliar imbricating sheaths. Leaves 2–5, arising from the basal node of tuber, alternate, lamina ovate-lanceolate to elliptic-lanceolate, 12–36 × 2.5–12 cm, entire, undulate, acute to subacuminate at apex, plicate, many-veined, with long petiolar sheathing base. Inflorescence 14–27 cm long, not exceeding the leaves, lateral, arising from the base of newly developed pseudobulbs; peduncle 11–24 cm long, erect, terete, bearing 3–4 tubular sheaths; sheaths oblong, acuminate at apex, greenish, membranous; rachis 2.5–3 cm long, mostly decurved towards the apex, laxly 6–14 flowered with 2 sterile bracts. Floral bracts oblong to lanceolate, 5–13 × 1.5–2 mm, shorter than pedicel plus ovary, sometimes longer, entire, acuminate at apex, membranous, green, obscurely 3-veined, externally pubescent; pedicel with ovary clavate, 5–10 mm long, green, ridged. Flowers 2–3 cm across, spreading, white, labellum with yellow disc near middle and purplish tinge at apex. Sepals subequal, oblong or oblong-lanceolate, entire, acute, 3–5-veined; dorsal sepal 1.3–2.2 × 0.6–0.7 cm; lateral sepals 1.4–2.4 × 0.7–0.8 cm, often oblique at base. Petals elliptic-obovate to oblong-obovate, broader than sepals, 1.4–2.3 × 0.7–1.2 cm, entire, obtuse at apex, weakly oblique at base, 5-veined. Labellum cymbiform, broadly ovate-cordate while spreading, 1.4–2 × 1–1.7 cm, sessile, ventricose at base, sac pointing backward, margin entire, undulate with erect lateral edges, slightly deflexed and emarginate at apex; disc pale to bright yellowish, often slightly padded, purplish towards apex, base with purplish-brown to creamy white to white short cellular hairs. Column oblong, 5–7 mm long, stout, hairy at base, slightly dilated above; stigma 1-lobed, ovate to dumbbell-shaped, slightly constricted at middle; clinandrium shallow, keeled inside; anther 2-loculed, broadly ovate-orbicular to orbicular-elliptic, 1.5–2.4 × 1.5–3 mm, locules pouch like, white with purplish tinge; pollinia 2, oblong–ovoid, c. 2 × 1.2 mm, deeply porate behind, yellow; caudicles hyaline, 1–1.2 mm long, subquadrate, dilated ­above; viscidium ovate, 0.4–0.7 mm long, toothed on both side, light yellowish-brown. Capsule 3–4.5 cm long, oblong-ellipsoidal, 6-ridged, drooping.
Flowering & Fruiting. – May–September.
Habitat. – In tropical moist deciduous open forests up to 1200 m elevation.
Distribution. – INDIA: Assam, Andhra Pradesh, Chhattisgarh, Gujarat, Jharkhand, Maharashtra, Mizoram (reported here), Odisha, Telangana, West Bengal (reported here); endemic.
Specimens examined. – INDIA: Assam, Jenkins s.n. (CAL, syntype of G. laxiflorum ). Mizoram, Hualtu Range, Tawi Wildlife Sanctuary, 13.03.2021 (flowered at rooftop plant conservatory of CAL on 24.06.2022), S. Sarkar & S. Chakraborty 41667 (CAL). West Bengal, Howrah district, Acharya Jagadish Chandra Bose Indian Botanic Garden (‘HBC’, in cultivation), Griffith s.n. (CAL, lectotype ofG. laxiflorum ); Paschim Bardhaman district, Garh Jungle, 08.06.2022, S. Mondal 3614A, 3614B (CAL).
Notes. – Geodorum laxiflorum is highly variable species. The most significant variation is in the relative length of the floral bract with respect to pedicel plus ovary. Griffith (1845), Bhatt et al. (2015), Veeranjaneyulu et al. (2017), Bhoyar et al. (2022) described/ illustrated bracts which were shorter than the pedicel plus ovary. During our study we have observed two kinds of bracts, even in the plants of same subpopulation – i) shorter than the pedicel plus ovary, and ii) longer than the pedicel plus ovary. The length of the bracts varies from 0.5 to 1.3 cm. The shape and size of anther are also significantly variable as the shape is broadly ovate-orbicular to orbicular-elliptic. The size of broadly ovate-orbicular anthers varies from 1.5–2 mm in length and 1.5–1.7 mm in breath, whereas the size of orbicular-elliptic anthers is from 2–2.4 mm in length and 2.7–3 mm in breath. The other variable characters in the species are length of the plants, colour of labellum, shape and size of sepals and petals, size of pollinarium, shape and size of pollinia (Figure 1).
In the protologue of G. laxiflorum , Griffith (1845) described the labellum with a patch of purplish, short cellular hairs on the adaxial surface near the base. These hairs are too tiny to be seen properly even with modern dissecting stereo microscope and thus, this character has not been described by the subsequent workers (Seidenfaden 1983; Misra 2004; Misra 2014; Bhatt et al. 2015; Veeranjaneyulu et al. 2017; Bhoyar et al. 2022). During our study we observed not only the microscopic cellular hairs near the base of labellum, but also variation in their colour, which range from purplish to purplish-brown to creamy white to white (Figure 1 k1, k2).
Geodorum laxiflorum was first described by William Griffith (Griffith, 1845) based on Major Jenkins’s collection from Assam, which flowered in the then Calcutta Botanic Garden (now Acharya Jagadish Chandra Bose Indian Botanic Garden, Howrah) in the month of May. Seidenfaden (1983) doubted the existence of any original material, except a “fine drawing by Griffith at K”. Misra (2004) followed Seidenfaden (1983) and mentioned the same in his work, though he did not see the Griffith’s K-drawing. Bhatt et al. (2015) designated Griffith’s drawing at K as lectotype of Geodorum laxiflorum . However, Bhatt et al. (2015) did not see the K-drawing which was evident from their citation of the lectotype. Dr Harry Smith, Curator-Botanist, Asia Team, Science Collections, Herbarium, Royal Botanic Gardens, Kew, sent us digital image of the only illustration of this species present at K and mentioned (pers. comm., 12.07.2022) – “the information on the sheet does not unequivocally suggest that it is indeed a drawing by Griffith”. We are also in same opinion that the K-drawing (K001535002, Figure 3) was not drawn by Griffith, but it is a copy from the original drawing drawn by M.C. Noble in 1889 and therefore, it is not an original material of G. laxiflorum as it postdates the publication of the name. Dr Henry Noltie, Royal Botanic Garden, Edinburgh, informed (pers. comm., 13.10.2022) that the K-drawing is undoubtedly an exact copy of the original Griffith’s drawing of CAL. In the 1880s there was a reciprocal exchange, i.e. drawings at CAL were copied for K and drawings at K were copied for CAL, especially of orchids. Dr Noltie also added “The name of the copy-artist is M.C. Noble, but I haven’t come across this name and don’t know if he/she did the copying at CAL (most likely) or whether the drawings were sent to Kew, copied by an artist there, and then returned to CAL”. The writing ‘Ic Herb Calcutta’ by J.D. Hooker and the writing ‘by M.C. Noble 1889’ on the K-drawing also confirms that the K-drawing was copied from Griffith’s original drawing at CAL. Though we did not found Griffith’s original drawing at CAL in spite of thorough search, we found one of the unnoticed type-specimens of G. laxiflorum at CAL (CAL0000086400, Figure 2b) which was collected by Jenkins from Assam and was mixed with other Orchid-specimens at the general herbarium of CAL. Though the flowers of the CAL-specimen are in bud condition, but undoubtedly it is one of the original materials ofG. laxiflorum . Griffith (1845) mentioned that Jenkins’s collected plants from Assam flowered later in May, and thus it is natural that the CAL-specimen was in bud condition when mounted. While describingG. laxiflorum , Griffith (1845) compared it with G. dilatatum R. Br. [= Geodorum recurvum  (Roxb.) Alston] and distinguished it from G. dilatatum in having thinly flowered spike, broad petals, and the round cochleariform entire labellum, which when spread out is of a cordate shape. Geodorum laxiflorumis also morphologically similar to G. densiflorum  (Lam.) Schltr., but can be readily distinguished from the later in having much shorter inflorescence, i.e. inflorescence not exceeding the leaves, absence of longitudinal, irregular, yellow to whitish callus on disc of labellum (but often slightly padded), and the labellum lacking crimson-purple venation and streaks below the disc. In G. densiflorum  the inflorescence usually exceeds the leaves, the disc of labellum with low but prominent, longitudinal, irregular (2-many dentate), yellow to whitish callus, and the labellum with crimson-purple venation and streaks below the disc. Further, the inflorescence of G. laxiflorum is often comparatively less flowered, lax and flowers are more open than that of G. densiflorum . We have traced out another interesting specimen at CAL (CAL0000055002, Figure 2a) with Griffith’s annotation (‘HBC’, i.e. Hortus Botanicus Calcuttensis) which was identified by Griffith as ‘Geodorum laxiflorum ’. This CAL-specimen is also with an inflorescence not exceeding the leaves and moreover, the flowers are much open and in completely blooming condition. This specimen also belongs to one of the original materials of G. laxiflorum as Griffith (1845) mentioned that Jenkins’s Assam-plants flowered in the Calcutta Botanic Garden. However, the other data written on the herbarium-label are not readable due to the damage of the label in the lower part, and due to unreadability of the date/ month/ year of collection. In December 1844 Griffith sailed for Malacca from India for the second time and could not return to India as he was seized with a fatal illness and died on 9 February 1845 in Malacca. Therefore, it is obvious that this CAL-specimen (CAL0000055002) annotated by Griffith predates the publication of G. laxiflorumand part of the original material of the name. Interestingly, this CAL-specimen (CAL0000055002) is very much matching with the K-drawing ofG. laxiflorum (especially with respect to two apical leaves, inflorescence and flowers) which was copied from Griffith’s original drawing at CAL (presently not traceable). The other existing original material of the name is the illustration [Icon Griffith (Geodorum laxiflorum ) , Calcutta J. Nat. Hist. 5: Pl. XXIV, tt. 1–7. 1845] published by Griffith (1845) in the protologue. Among the all available original materials of G. laxiflorum , the CAL-specimen ‘CAL0000055002’ is the most suitable choice for lectotypification as the diagnostic characters of G. laxiflorumare more evident in this specimen. Hence, we are superseding the lectotypification by Bhatt et al. (2015) in accordance with Art. 9.19 of the ICN (Turland et al. 2018) and designating the CAL-specimen (CAL0000055002) as lectotype of G. laxiflorum according to Art. 9.3, 9.12 of the ICN (Turland et al. 2018) as it has precedence over the illustration published in the protologue. It is worth mentioning that another name under the genus, viz. G. rariflorum Lindl. [=G. densiflorum (Lam.) Schltr.], was also based on Jenkins’s collection from Assam, i.e. specimen with same label-data (‘Assam, Jenkins’). However, the types of G. laxiflorum (CAL!) and ofG. densiflorum (K!) are taxonomically different.
Chase et al. (2021a) recently reduced Geodorum underEulophia R. Br. based on phylogenetic study and subsequently proposed (Chase et al., 2021b) to conserve Eulophia overGeodorum. Chase et al. (2021a) treated Geodorum laxiflorum  Griff. under Eulophia as E. diffusiflora M.W. Chase, Kumar & Schuit. (replacement name). However, treatingEulophia as a conserved name over Geodorum is subject to acceptance the proposal in the XX International Botanical Congress to be held in Madrid, Spain in 2024 and therefore, Geodorum must be treated as correct name at present due to priority. Hence, E. diffusiflora M. W. Chase, Kumar & Schuit. is treated here as a homotypic synonym of G. laxiflorum  Griff. until Eulophiais conserved against Geodorum .