Homalium longistaminum H. Perrier in Mém. Mus. Natl. Hist. Nat. 13: 287. 1940

Applequist, Wendy L., 2018, A revision of Homalium sect. Odontolobus (Salicaceae) endemic to Madagascar, Candollea 73 (1), pp. 27-48 : 33-34

3. Homalium longistaminum H. Perrier in Mém. Mus. Natl. Hist. Nat. 13: 287. 1940 .

Lectotypus (designated here): MADAGASCAR. Prov. Toliara: vallée de la Manambolo , rive droite (bassin du Mandrare) aux env. d’Isomono ( confluent de la Sakamalio ), 400-900 m, XII.1933, buds & fl., Humbert 12914 ( P [ P04679979 ]! ; isolecto-: L [ L0010953 ] image seen, P [ P04679980 ]!) .

Tree to 12 m tall, 30 cm dbh; young twigs glabrous or minutely pubescent. Leaves: petiole 4-11 mm long, glabrous (sparsely, minutely pubescent); blade irregularly elliptical to broadly elliptical or ovate (lanceolate), (3.2-)3.5-7.5 × 1.6-3.3(- 4.8) cm; base convex to rounded (attenuate at extreme base); margins irregularly crenate apically to crenate-serrate for most of their length; apex acute to obtuse or rounded (short-acuminate). Inflorescences racemose, (2.2-) 4-6.5 cm long, canescent or in part moderately pubescent; flowers often borne in clusters of 2 or 3, on pedicels 0.3-1.4 mm long; bracts transversely to broadly deltoid; bracteoles very thick, to subterete at base, densely pubescent (absent or rapidly caducous). Flowers 6- or 7-merous, pale or yellowish green; sepals deltoid to ovate, (0.3-)0.4-0.5(-0.6) mm long; petals oblong to somewhat obovate, 0.8-1.2 mm long, margins short-ciliate and both surfaces pubescent, densely so abaxially and usually at base adaxially, apex rounded or obtuse; filaments 1.1-1.7 mm long; upper surface of ovary canescent; styles (3-)4(-5), 1.1-1.7 mm long.

Vernacular names. – “Tsimalagnilamba” (Eboroke 980); “Tsimalamba” (Humbert 12914).

Distribution, ecology and conservation status. – Homalium longistaminum is confined to a limited area in southeastern Madagascar, where it occurs mostly in low-elevation humid forests. The fact that very few collections are available, although both Andohahela and Ranopiso are relatively well-collected, suggests that the species is rare in its native range. Four collections are known, pertaining to only three distinct localities, and giving an AOO of no more than 12 km 2. Two of these three are in the area of Andohahela RNI, hence protected. However, the species should be considered “Vulnerable” [VU B1ab(iii)+B2ab(iii)] based on its small AOO (<20 km 2) and number of locations (≤ 5).

Note. – In publishing this species, PERRIER DE LA BÂTHIE (1940) did not note that there were two sheets of the type collection at P; Sleumer incorrectly marked both as “ holotype ”. The sheet numbered P04679980 has a determination label by Perrier, while the sheet numbered P04679979 has notations on the label in the same handwriting that read “ Homalium (Blackwellia) longistaminum H. Perr. ”, with the addition of “n. sp.”, and “ Type ” (double underlined). The latter sheet is in better condition, having a fragment packet that contains partially open flowers; it would certainly be a more suitable type and Perrier de la Bâthie probably intended it as such. However, since both sheets were used by Perrier de la Bâthie and no distinction between them was made in the protologue, they are regarded as syntypes and it is therefore necessary to designate a lectotype.

Additional material examined. – MADAGASCAR. Prov. Toliara: RNI d’Andohahela , parcelle n° 2 , 24°49’49’’S 46°32’15’’E, 30-50 m, 16.III.1994, Andrianarisata et al. 101 ( MO [2 sheets]) ; Ranopiso, Evasia , 24°46’S 46°41’E, 350 m, s.d., post-fl., Eboroke 980 ( G, MO) ; Andohahela, parcelle n° 2 , Ihazofotsy , 24°50’S 46°33’E, 50-200 m, 2-5.III.1993, fr., Randriamampionona 152 ( MO, P) .