Machilus bokorensis Yahara & Tagane, 2016

Yahara, Tetsukazu, Tagane, Shuichiro, Mase, Keiko, Chhang, Phourin & Toyama, Hironori, 2016, Flora of Bokor National Park V: Two new species of Machilus (Lauraceae), M. bokorensis and M. brevipaniculata, PhytoKeys 65, pp. 35-46 : 37

Machilus bokorensis Yahara & Tagane sp. nov. Figs 1 , 2

Machilus odoratissima (non Nees) sensu H.Liou, Laurac. Chine & Indochine: 53 (1932), for the specimen collected from Nord de Kampot (P, no. 14625).

Diagnosis.

Similar to Machilus odoratissima Nees in elliptic-lanceolate or oblanceolate, glabrous leaves and subterminal inflorescences, but differing in having sericeous inflorescence rachis (Fig. 2c ; vs. glabrous in Machilus odoratissima ), perianth lobes pubescent on both surfaces (Fig. 2c ; vs. outside almost glabrous), ca. 1 mm long staminodes (vs. ca. 2 mm long), and twigs drying blackish grey (vs. reddish). Similar to Machilus parviflora Meisn. among Indochinese species in having large terminal buds, but differing in bud scales densely puberulent outside (vs. densely golden hairy outside in Machilus parviflora ).

Type.

CAMBODIA. Kampot Province, Bokor National Park, dense evergreen forest on the plateau of Mt. Bokor , 10°39'19.5"N, 104°03'36.6"E, alt. 933 m, 16 Feb. 2013, with flowers, Tagane S., Toyama H., Wachi N., Ichihasi R., Mase K., Zhu M., Chhnang P. 5475 (holotype KYO!, isotypes BKF!, FU!, K, P, PNP!) .

Description.

Small tree, 10 m tall. Branchlets glabrous, blackish when dry, sparsely lenticellate, old branches blackish grey or blackish grey brown. Terminal buds 3-7 mm long, bud scales broadly ovate to oblanceolate, densely puberulent outside, glabrous or very sparsely pubescent inside. Leaves alternate, blades elliptic-lanceolate, oblanceolate, (3-)7.5-11.5(-18.5) × (1.2-)2.5-4.0(-5.4) cm, thickly leathery, base cuneate, margin entire, slightly revolute, apex usually acute to obtuse, occasionally acuminate or rotund, developing leaves glabrous adaxially, sericeous abaxially, glabrous and densely foveolate on both sides when old, midrib concave adaxially, elevated abaxially, lateral veins 9-12 pairs, flat adaxially, slightly prominent abaxially, tertiary veins reticulate to scalariform-reticulate; petioles (0.5-)0.8-1.3(-2.5) cm long, glabrous. Inflorescences paniculate, subterminal, usually arising from near base of newly sprouted branchlets, (4.0-)6.0-13.0 cm long, sericeous, with 5-8 lateral branches. Pedicels 3-5 mm long, sericeous, bracts linear, 1-4 mm long, abaxially yellowish brown pubescent, adaxially glabrous, caducous. Flowers yellowish green; perianth lobes 6, oblong-elliptic, slightly unequal, outer ones, ca. 6.8 × 2.4 mm, inner ones ca. 7 × 2.5 mm, minutely pubescent on both surfaces. Stamens 9, subequal, 3.5-4 mm long, hairy at base, glands of 3rd series stipitate, ca. 0.4 mm long; staminodes 3, ca. 1 mm long, stipitate, glabrous. Ovary subglobose ca. 1.5 mm in diam., glabrous. Style 2.5-3 mm long, glabrous. Fruits subglobose, 7-8 mm in diam., glabrous, blackish when dry, perianth lobes spreading.

Ohter specimens examined.

Cambodia, Bokor National Park [alt. 1043 m, 10°37'16.8"N, 104°01'52.3"E, 10 Dec. 2013, Toyama et al. 6258 (BKF, FU, PNP); alt. 1042 m, 10°38"N, 104°01.4'E, 9 Mar. 2001, with fruits, Middleton & Monyrak 643 (P); alt. 1014 m, 10°38'12.6"N, 104°02'06.4"E, 4 Dec. 2011, Toyama et al. 1556 (FU, PNP); ibidem, Toyama et al. 1575 (FU, PNP); alt. 1011 m, 10°38'11.2"N, 104°02'09.0"E, Toyama et al. 1725 (FU, PNP); alt. 928 m, 10°39'19.5"N, 104°03'36.6"E, Toyama et al. 2754 (FU, PNP); alt. 903 m, 10°39'35.4"N, 104°03'03.1"E, Toyama et al. 3167 (FU, PNP); alt. 871 m, 10°39'48.8"N, 104°02'53.3"E, 17 Dec. 2013, with flowers, Fuse et al. 6227 (BKF, FU, PNP)] .

Distribution.

Cambodia (endemic to Mt. Bokor).

Habitat and ecology.

Machilus bokorensis is commonly found in moist evergreen forest on the top plateau of Mt. Bokor. Flowering specimens were collected in December and February and fruiting specimens in March.

GenBank accession No.

Toyama et al. 1575: AB987667 (rbcL), AB987666 (matK), AB987665 (ITS).

Preliminary conservation assessment.

Machilus bokorensis is commonly found in higher elevations in Mt. Bokor. Since many mature individuals were found in the protected areas, we suggest the status for this species as Least Concern (LC) according to IUCN Red List criteria ( IUCN 2012).

Note.

Among five species we collected in Mt. Bokor, this species is most common and agrees with the description of " Machilus odoratissima " in the key of Liou (1934) who recorded " Machilus odoratissima " from Nord de Kampot, corresponding to Mt. Bokor. Thus, we consider that this species is " Machilus odoratissima " recorded by Liou (1934), although we could not examine the specimen of Poilane 14625 (P) cited by Liou (1934) because it is currently on loan. In Indo-china, Machilus plants similar to this species have been identified as Machilus odoratissima for a long time ( Lecomte 1914; Liou 1934; Phon 2000). However, Machilus bokorensis is distinct from Machilus odoratissima distributed in Nepal, E Himalaya, Assam-Burma in sericeous inflorescence rachis (vs. glabrous in Machilus odoratissima ; Pendry 2012), perianth lobes pubescent on both surfaces (vs. outside almost glabrous), ca. 1 mm staminodes (vs. ca. 2 mm), and blackish grey twigs (vs. reddish). In Cambodia, we collected sterile specimens of Machilus spp. morphologically similar to Machilus bokorensis in Central Cardamon and Seima protection forests but those are morphologically distinguishable and not sister to Machilus bokorensis in our unpublished phylogenetic tree constructed by rbcL, matK and ITS sequences. " Machilus odoratissima " is recorded from Mulu-prey, Preah Vihear ( Lecomte 1914). The specimens from Mulu-prey (Harmand s.n., P) are, however, different from Machilus bokorensis in having naked terminal buds and scalariform tertiary veins. Lecomte (1914) and Liou (1934) recorded " Machilus odoratissima " also from Laos and Vietnam, but we have not found specimens from Laos and Vietnam identical with Machilus odoratissima . As far as we know, Machilus odoratissima is not distributed in Cambodia, Laos, Thailand and Vietnam. The relationship between Machilus bokorensis and the specimens of Mulu-prey, Laos and Vietnam remains to be further examined. At present, we consider that Machilus bokorensis is endemic to Bokor, Cambodia. According to our unpublished ITS tree, this species is sister to Machilus rimosa (Blume) Blume distributed in Indonesia, but distinct from Machilus rimosa in thickly leathery leaves densely foveolate on both sides (vs. thinner leaves not densely foveolate in Machilus rimosa ) and perianths larger (6.8-7 mm long vs. ca. 3.5 mm long).

Figures

Figure 1. Machilus bokorensis Yahara & Tagane. a flowering branch, b abaxial lower surface of lamina c flowers d buds e holotype: Tagane et al. 5475 (KYO), scale bar = 10 cm f inflorescence, scale bar = 1 cm. Photographs: a-c by S. Tagane, d by K. Fuse.

Figure 2. Machilus bokorensis Yahara & Tagane. a flowering branch b top of branch c flowers d stamen in 1 st whorl e stamen in 2 nd whorl with staminode f stamen in 3 rd whorl with glands g pistil h outer perianth lobes i inner perianth lobe j, k bud scales. Materials from Tagane et al. 5475 (KYO). Drawn by S. Tagane.