This mistletoe was commonly found on the higher canopies of the host where it partially or completely defoliated the infected branches. The heavily degraded forest had Q. semecarpifolia as the dominant tree with Alnus nepalensis D. Don, Betula alnoides Buch.-Ham. ex D. Don, and Pieris formosa as associated tree species.

An initial search of the KATH herbarium showed that no mistletoes matched the collected specimen. Examination of this specimen and a thorough literature search confirmed that this was Loranthus lambertianus, a species listed in the Annotated Checklist of the Flowering Plants of Nepal; however, that website did not provide any details regarding the occurrence and distribution of the mistletoe in the country. Further, it was found that no previous checklist of the flowering plants of Nepal, including the works of Hara et al. (1982) and Press et al. (2000), included this mistletoe in their species lists. Because the Latin protologue by Schultes and Schultes (1829) was the only description of the species, the following is provided.

Shrubs, deciduous, erect, to 1.5 m tall, glabrous, producing large ball-like haustoria, epicortical roots absent. Stems pseudo-dichotomously branched, distinctly articulated; older branches dark brown, terete, lenticelate; younger branches dark brown, covered with brown papery caducous winter bracts, terete, smooth. Leaves alternate, simple, borne on brachyblasts, petiole 2–3 mm long; lower leaves entire, ovate, ca. 1 cm long; upper leaf blades entire, broadly to narrowly ovate, oblong, sometimes obovate, 1.7–4 cm long, thin and papery, base cuneate, apex acute or rounded, lateral veins obscure, in 3 to 4 pairs, more prominent on upper surface. Inflorescences spikes, solitary, terminal, on older branches, 3–3.5 cm long, peduncles subangular, 3 mm long. Flowers bisexual, epigynous, 10–15, sessile, arranged opposite and sub-opposite in pits (fovea) of inflorescence axis, evenly spaced, angled slightly acropetally, subtending bract minute, forming part of foveal rim, 5–6 mm wide, 6-merous; calyculus minute, entire; petals 6, free, valvate, pale yellow, lanceolate or oblong, 2.8–3 mm long, apex acute, reflexed at anthesis; stamens 6, filaments 1.3–1.5 mm long, adnate one half their length to the base of the petals; anthers 3/4 width of the petal bases, white, with two smaller basal locules and two larger terminal ones; ovaries inferior, the lower portions sunken into the pits; style 1–1.5 mm long, stout; stigma capitate, flattened, obliquely lobed with an undulate and finely papillate margin. Flowering: April–June. Fruiting: assumed June–August.

This description matches very well with the one provided by Schultes and Schultes (1829), with the exception that they indicated the flowers were 5- vs. 6-merous. Comparing the type of Loranthus lambertianus with Devkota 1421 (Fig. 1) shows the overall similarity between the two. Unfortunately, the photograph of the type does not provide sufficient resolution to confirm flower merosity (the specimen was not examined directly). It is possible that Schultes erred in the description of the flower, however, this seems unlikely since he placed this species in section “b. Flores pentandri, 2. Inflorescentia terminali. More likely is the fact that species of Loranthus show plasticity in floral merosity, e.g., 4-, 5- and 6- merous flowers can occur on the same plant. This was observed by Danser (1936) who said “Moreover the number of petals appears not to be constant in Hyphear [Loranthus] europaeum, as its flowers are in general 6-merous, but partly 5 and even 4-merous.”

Danser (1931) proposed a new system of classification for the Old World Loranthaceae. His second of two keys concerned Hypheatinae (Loranthinae of Engler) that distinguished Hyphear from Helixanthera by the former having inflorescences as spikes and globose anther thecae and the latter having spikes or racemes and oblong anther thecae. Danser (1938) said “Hyphear is very closely related to Helixanthera, and, if it will finally appear undesirable to elevate the very different sections of the latter genus to the rank of genera (about which I still am in doubt), it will be better to consider also Hyphear as a section of Helixanthera.”

Balle et al. (1960) proposed conserving the name Loranthus Jacq. over Hyphear and this was accepted at the Edinburgh International Botanical Congress in 1964. Her main focus was upon Loranthus europaeus, but with that name transferred, other species of Hyphear by Danser (1929) were also moved (back) into Loranthus. Thus, Hyphear lambertianum (Schult. & Schult. f.) Danser became L. lambertianus Schult. & Schult. f.

Although Barlow (1997) treated Helixanthera and Loranthus as separate genera, he followed Danser by considering them closely related. Indeed, these two are the last to be distinguished in his key to genera. The couplets were “flowers hermaphrodite, anthers linear” for Helixanthera and “flowers mostly unisexual, anthers globose to subglobose” for Loranthus. Only L. odoratus is present in Flora Malesiana, and regarding flower sexuality, Barlow wrote “flowers probably functionally unisexual but often with vestigial organs of the other sex.” His description only mentions flowers with an androecium whereas the illustration shows a plant in fruit. The specimen of L. odoratus examined by coauthor MPD from Nepal had bisexual flowers, but as discussed in Nickrent et al. (2021), the sexual mode of this species requires further research. Because of doubts about the systematic value of flower merosity and sexuality, Danser (1936) suggested that only two species of Loranthus (as Hyphear) might exist.

The key to genera of Loranthaceae in Flora of China (Qiu et al., 2003) included several characters to differentiate Helixanthera from Loranthus. These were flowers sessile vs. pedicellate, flower merosity, corolla color, corolla size, and anther shape (ellipsoid in Helixanthera vs. ovoid, biglobose, or absent in Loranthus). Although flowers are generally larger in Helixanthera than in Loranthus, most character states overlap among the various species in the two genera or only apply to certain species. It appears that all Helixanthera have bisexual flowers whereas Loranthus has variable flower sexuality, including some species with bisexual flowers. Compared with Helixanthera, anther shapes in Loranthus are relatively homogeneous. But the description “globose” or “subglobose” that applies to species such as L. europaeus does not apply to others such as L. odoratus that has elliptic anthers much like those seen in various Helixanthera species.

Rajasekaran (2007) made two new combinations: Helixanthera lambertiana (Schult.) Rajasekaran and H. odorata (Wall.) Rajasekaran but provided no discussion or justification for these transfers. These concepts were carried over into the Flora of India treatment (Rajasekaran 2012) which is strongly influencing the Flora of Nepal project.

Along with all members of Santalales, Loranthaceae has been the subject of numerous molecular phylogenetic studies. Multigene studies that sampled representatives of both Helixanthera and Loranthus include Vidal-Russell and Nickrent (2008), Su et al. (2015), Liu et al. (2018), and Nickrent et al. (2019). In all of these, the genus Loranthus is sister to Cecarria obtusifolia (Merr.) Barlow and that clade did not include Helixanthera (Fig. 2A). More recently, a detailed molecular phylogenetic and morphological cladistic study of all species of Loranthus was conducted (Nickrent et al., 2021). Whole chloroplast genome sequences and nuclear ribosomal DNA supported the monophyly of Loranthus (nine species) and the sister relationship between this genus and Cecarria (Fig. 2B). The classification of Loranthaceae proposed in Nickrent et al. (2010) placed both Loranthus and Helixanthera in tribe Lorantheae, however, they were segregated into subtribes Loranthinae and Dendrophthoinae, respectively.

In contrast to the well-supported monophyly of Loranthus, such is not case with Helixanthera (Fig. 2A). This mistletoe contains ca. 40 species distributed from Africa through southern Asia and into eastern Asia and Malesia. Five species were sampled in the molecular study by Liu et al. (2018) wherein those representatives were placed on three different clades of Lorantheae. Although modern taxonomists consider all of these congeneric, the molecular evidence strongly suggests that the assemblage is polyphyletic and separate genera should be recognized. This would fit with past views of workers who erected a number of genera to account for the wide range of morphological variability e.g., Acrostachys Tiegh., Chiridium Tiegh., Coleobotrys Tiegh., Dithecina Tiegh., Lanthorus C. Presl., Leucobotrys Tiegh., Phoenicanthemum (Blume) Blume, Strepsimela Raf., and Sycophila Welw. ex Tiegh. Despite the problems of generic circumscription surrounding Helixanthera, they do not affect the composition of Lorantheae subtribe Loranthinae.