Jumellea maxillarioides is known from Madagascar and Comoros. The species is recorded from 35 collections (17 occurrences). Eight of these collections, (Cowan, W.D. 26, Forsyth-Major, C.I. 452, Hillerman, F. 58, Mason, L.M. 1663, Mason, L.M. 1721, Mason, L.M. 1851, Stewart, J. 1106 and Rakotoarivelo 227) were made with no precise locality information and thus not taken into account in this assessment. This species is also known from one observation recorded on iNaturalist. However, because precise GPS coordinates are not available, this observation was not considered in this assessment. It is also known for one collection and one location in Comoros. Four collections representing four occurrences have been recorded in four protected areas, Manjakatompo Ankaratra Natural Resources Reserve (one occurrence), Maromizaha Natural Resources (one occurrence), Ambositra-Vondrozo Forest Corridor (COFAV) (one occurrence), and the Protected harmonious landscape of the Anjozorobe-Angavo complex (one occurrence). Jumellea maxillarioides is also known from twenty-one collections representing four occurrences from Angavokely (one occurrence), Tsiazompaniry (two occurrences), and Maharavana-Antoetra (one occurrence) made in unprotected forests that are subjected to selective logging, shifting agriculture practices, production of charcoal, grazing and annual bushfire. This species is thus known from 27 georeferenced collections representing nine occurrences.

The extent of occurrence (EOO) of J. maxillarioides is estimated to be over 142,984 km² (far exceeding the limits for Vulnerable status under criterion B1) and its minimal area of occupancy (AOO) is estimated to be 36 km² (which falls in the limits for Endangered status under the criterion B2). These nine occurrences represent a total of nine locations (sensu IUCN 2019) with respect to the main threats, annual bushfire, and shifting agriculture practices falling within the limit for Vulnerable status. It is inferred that the past loss of its habitat has induced a strong decline in EOO, AOO, habitat extent and quality, the number of subpopulations, and mature individuals in the past ten years. Jumellea maxillarioides would have been assigned a Vulnerable status under criterion B. We project that the occurrences (Petterson 190, 508, 526, 557, 606; Perrier 12978, 16051; ANT 362; Rabarimanarivo 670 and Decary s.n.) will become extirpated in the near future due to the Eucalyptus plantation, shifting agriculture practices, charcoal producing, grazing and annual bushfire reducing the AOO from 36 km² in 2015 to 20 km² in 2030, a population reduction of 56%, where the cause of the reduction, forest clearing, may not have ceased or may not be reversible based on the decline in the area of occupancy, which is under the threshold of Endangered status under criterion A. Jumellea maxillarioides is thus assessed as EN A4c.

Jumellea maxillarioides is known from Madagascar where it occurs in the former provinces of Antananarivo in Analamanga, Vakinankaratra Regions (Angavokely, Tsiazompaniry, Ankaratra), of Fianarantsoa in Amoron'i Mania, Haute-Matsiatra Regions (Maharavana-Antoetra, Ambondrombe), and of Toamasina in Alaotra-Mangoro Region (Ambodikija, Maromizaha). It is also recorded from the Comoros.

The population of Jumellea maxillarioides is currently thought to be decreasing since the species habitat is threatened by annual bushfires, shifting agriculture practices, selective logging, charcoal production, and grazing. The number of mature individuals of J. maxillarioides is not known and cannot be estimated since the species is an epiphyte on the trunks of trees or a lithophyte on the mossy inselbergs.

Jumellea maxillarioides is an epiphytic or lithophytic herb growing on moss and lichen-covered trees in humid and subhumid forests, on the inselberg/rock faces of the central plateau and the eastern escarpment at elevations of 1,000 to 1,853 m asl (Madagascar Catalogue 2020).

The species is threatened by annual bushfires and shifting agriculture practices. It is known from four occurrences made in unprotected forests that are subjected to annual bushfires, shifting agriculture practices, grazing, selective logging, and production of charcoal.

There is no available information on the use and trade of this species, but it may be sought after by specialist collectors.

Four collections representing four occurrences have been recorded in four protected areas, the Manjakatompo Ankaratra Natural Resources Reserve (one occurrence), the Maromizaha Natural Resources Reserve (one occurrence), the Ambositra-Vondrozo Forest Corridor (COFAV) (two occurrences), and the Protected harmonious landscape of the Anjozorobe-Angavo complex (one occurrence). The species is included in Appendix II of CITES. It is recorded in four ex situ collection (BGCI 2019). Individuals from this species have been brought to cultivation in the Antananarivo shade house. Ex situ conservation is recommended (micro-propagation, seed banking). The species should be included in the Malagasy protected species list. Further awareness building is recommended for local communities and national authorities.