Humbertacalia neoalleizettei (Humbert) C. Jeffrey

Rabarimanarivo, Marina N., Callmander, Martin W. & Calvo, Joel, 2023, Synopsis of Humbertacalia (Compositae), a genus endemic to Madagascar and Réunion, Adansonia (3) 45 (7), pp. 93-113 : 103-104

7. Humbertacalia neoalleizettei (Humbert) C. Jeffrey

( Fig. 3 )

Kew Bulletin 47 (1): 83 ( Jeffrey 1992).

Senecio neoalleizettei Humbert , Notulae Systematicae 15 (4): 374 ( Humbert 1959).

— Typus: Madagascar. Diana Region [Prov. Antsiranana], Massif du Tsaratanana , plateaux supérieurs et hauts sommets de l’Amboabory à l’Antsianongatalata , flanc sud de l’Antsianongatalata, [14°01’30”S, 48°59’00”E], 2600- 2700 m, XI-XII.1937, fl., Humbert 18479 (lecto-, designated here, P [ P00557630 ]; isolecto-, P [ P00557629 ]!) ( Fig. 3 ); ibid. loco, flanc sud de l’Amboabory , [14°01’30”S, 48°59’00”E], 2400- 2500 m, XI-XII.1937, fl., Humbert 18372 (syn-, G [ G00398317 ]!, P [ P02397528 , P02397529 , P02397530 , P03420990 , P04416356 , P04416357 ]!, TAN!) .

ETYMOLOGY. — The epithet neoalleizettei honors Aymar Charles d’Alleizette (1884-1967), a French military administrator who was stationed in Madagascar in 1906. D’Alleizette was interested in botany and collected many botanical specimens.

VERNACULAR NAMES. — Unknown.

DISTRIBUTION AND ECOLOGY. — Humbertacalia neoalleizettii is known only from Tsaratanana massif, in montane bioclimate of northern Madagascar (Diana Region). It occurs on plateau or slope of remnant medium altitude moist evergreen forest and montane ericoid thicket, at high elevation of 2400-2750 m.

CONSERVATION STATUS. — Humbertacalia neoalleizettii has a narrow distribution with an area of occupancy (AOO) of 8 km 2 and known from two locations. The species grows on plateau or slope of Tsaratanana massif at high elevation within the protected area. The montane ericoid thicket in the vast summit plateau is vulnerable and under threat (see comments under H. amplexifolia ) but the known distribution of H. neoalleizettii also includes remnant medium altitude moist evergreen forest. These forests are not threatened at these altitudes by illegal cannabis plantations. Therefore, H. neoalleizettii is assessed as “Endangered” [EN B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)] according to IUCN Red List Categories and Criteria ( IUCN 2012).

ADDITIONAL SPECIMENS EXAMINED. — Madagascar. Diana Region [Prov. Antsiranana]: Tsaratanana massif, between Tsaratanana peak and Maromokotro , 14°01’59”S, 48°58’49”E, 2720 m, 19.X.2001, fl., Lowry et al. 5429 ( MO, P [ P02397889 ], TAN); ibid. loco, plateau supérieur du massif (Tsiatongatalata), [14°01’30”S, 48°59’00”E], 2700-2750 m, 14.XII.1966, fl., Service Forestier 27088 ( P [ P02397527 ], TEF [ TEF000676 ]) .

DESCRIPTION

Leaves petiolate; leaf laminas 4.5-8 × 2-4.2 cm, lanceolate to elliptic, base cuneate, apex acute, margins finely dentate to crenate, glabrous on both surfaces, venation pinnate (conspicuous on both surfaces, including tertiary veins), rather coriaceous; petioles up to 1.5 cm long. Synflorescences mostly terminal, thyrsoid-paniculiform. Capitula pedunculate (peduncles 2-4 mm long); involucres rather cylindrical, glabrous, somewhat swollen at base; involucral bracts 5, 2.7-3 × 0.6- 1.3 mm; supplementary bracts 1-3, 0.7-0.9 mm long. Florets c. 5, 4-4.4 mm long; corollas tubular, 5-lobed, whitish; anther bases short-caudate, a third to a half as long as filament collar; style branches obtuse with a crown of sweeping trichomes. Achenes 2.6-2.9 × 0.5-0.7 mm, rather cylindrical, c. 6-ribbed, glabrous, straw-coloured; pappus 3.8-4.1 mm long, whitish.

NOTES

This species is easily recognized by its glabrous, finely dentate to crenate leaves, the involucres composed of five involucral bracts, and the pedunculate capitula. This latter character distinguished it from Humbertacalia pyrifolia (Bojer ex DC.) C. Jeffrey , a similar species that has sessile or subsessile capitula, usually arranged in glomerules.

The protologue is ambiguous when designating the type of the name because Humbert cited two collections as follows: “ Humbert 18372, 18479 (Holotype P)”. Because the indicated elevation rank is “entre 2400 et 2700 m alt.”, where “ 2400 m ” corresponds to the lower elevation of Humbert 18372 and “ 2700 m ” the higher elevation of Humbert 18479, it is quite clear that Humbert considered both collections as the type material. The use of the term “ holotype ” to denote what is in fact syntypes is an error to be corrected. Herein, we designate the specimen P00557630 corresponding to Humbert 18479 as the lectotype of the name ( Fig. 3 ); an isolectotype is also kept at P.

Figures

FIG. 3. — Lectotype of Senecio neoalleizettei Humbert, Humbert 18479 (P00557630).