Clavistigmeae T. Y. Tu and P. W. Xie

Tu, Tieyao, Cai, Jie, Razafimandimbison, Sylvain G., Hu, Xiaoying, Xia, Qian, Yang, Hong, Gu, Shiran, Huang, Tianyi, Zhao, Zhongtao, Shi, Miaomiao, Wang, Xiangping, Li, Shijin, Xie, Peiwu, Wen, Jun & Zhang, Dianxiang, 2024, Biphyly of the genus Wendlandia and establishment of a new tribe Clavistigmeae and a new genus Clavistigma of Rubiaceae from Asia, Biological Diversity CLXVI (CLXVI), pp. 1-17 : 13-14

5.2 | Clavistigmeae T. Y. Tu and P. W. Xie , trib. nov. Nomenclatural type of the tribe: Clavistigma T. Y. Tu and P. W. Xie

5.2.1 | Diagnosis

The new monotypic tribe Clavistigmeae is characterized by a combination of the following characters: leaves arranged distichously or whorled 3–4. Ovary 2‐celled with multiple ovules per locule on peltate axile placentas at the central of the axile; styles coiled in the flower buds and pollens shed on the stigmas before anthesis; stigmas clavate. Capsules open apically and dehisce septicidally. Seeds elongated and often trianglular to square pyramidal. The arrangement of the leaves, the clavate stigmas, the dehiscent way of fruits, and the seed morphology of the Clavistigmeae are different from any of the other tribes in the Vanguerieae alliance.

5.2.2 | Description

Shrubs. Leaves simple, opposite, usually distichous, infrequently whorled of three or more on sterile shoots or at nodes, subsessile; leaf blade entire; stipules caducous to persistent, entire. Inflorescences axillary or pseudoterminal, paniculate with pairs of opposite decussate or ternate branches; lateral branches 1‐2 orders, usually subtended by leaf‐ like bracts, decreasing in size distally. Flowers shortly pedicellate. Hypanthium ellipsoid to subglobose; limb deeply lobed. Corolla tubular‐ funnelform. Anthers partially exserted. Style coiled in the flower buds and pollens shed on the stigmas before anthesis. Stigmas clavate. Ovary 2‐celled, ovules multiple in each cell on peltate axile placentas at the central of the axile. Capsules subglobose or ellipsoidal, calyx limbs persistent, pericarps woody, open apically and dehiscent septicidally; seeds triangle to square pyramidal, or irregular in shape.

5.2.3 | Distribution and habitat

China, Bhutan, northern India, Nepal, northern Thailand. In tropical or subtropical forests or in thickets; alt 200–1500 m.

5.3 | Clavistigma T. Y. Tu and P. W. Xie , gen. nov. ≡ Wendlandia ser. Clavigera Cowan in notes R. Bot. Gard. Edinb. 16: 233–314, 1932 – Type: Clavistigma pendulla (Wall.) T. Y. Tu and P. W. Xie ≡ Rondeletia pendula Wall. in Roxburgh, Fl. Ind. 2:140. 1824 ≡ Wendlandia pendula (Wall.) DC. , in Prodr. 4:412. 1830

5.3.1 | Diagnosis

The new monotypic genus Clavistigma is characterized by a combination of the following characters: Leaves arranged distichously or whorled 3‐4 often on the pendent branches. Ovary 2‐celled with ovules 10–15 per locule on peltate axile placentas at the central of the axile; styles coiled in the flower buds and pollens shed on the stigmas before anthesis;stigmas clavate. Capsules open apically and dehiscent septicidally. Seeds elongated and often triangle to square pyramidal, testae reticulate, with cells irregularly multilateral and cell margins undulate. The arrangement of the leaves, the clavate stigmas, the dehiscent way of fruits, and the seed morphology of the genus are different from any of the other genera in the Vanguerieae alliance.

5.3.2 | Description

Shrubs. Leaves simple, opposite, usually distichous, infrequently whorled of three or more on sterile shoots or at nodes, subsessile; leaf blade entire; stipules caducous to persistent, entire. Inflorescences axillary or pseudoterminal, paniculate with pairs of opposite decussate or ternate branches; lateral branches 1‐2 orders, usually subtended by leaf‐ like bracts, decreasing in size distally. Flowers shortly pedicellate. Hypanthium ellipsoid to subglobose; limb deeply lobed. Corolla tubular‐ funnelform. Anthers partially exserted. Style coiled in the flower buds and pollens shed on the stigmas before anthesis. Stigmas clavate. Ovary 2‐celled, ovules multiple in each cell on peltate axile placentas at the central of the axile. Capsules subglobose or ellipsoidal, calyx limbs persistent, pericarps woody, open apically and dehiscent septicidally; seeds triangle to square pyramidal, or irregular in shape.

5.3.3 | Distribution and habitat

China, Bhutan, northern India, Nepal, northern Thailand. In tropical or subtropical forests or in thickets; alt 200–1500 m.

5.4 | Clavistigma pendula (Wall.) T. Y. Tu and P. W. Xie , comb. nov. ≡ Rondeletia pendula Wall. in Roxburgh, Fl. Ind. 2:140. 1824 ≡ Wendlandia pendula (Wall.) DC syn. nov. in Prodr. 4:412. 1830 ‐ Type: Nepal, Wall. Cat. No. 6275 (HT: K!, IT: BM!, BR!)

5.4.1 | Diagnosis

Leaves arranged distichously or whorled 3‐4 often on the pendent branches. Ovary 2‐celled with ovules 10–15 per locule on peltate axile placentas at the central of the axile; styles coiled in the flower buds and pollens shed on the stigmas before anthesis; stigmas clavate. Capsules open apically and dehiscent septicidally. Seeds elongated and often triangle to square pyramidal, testae reticulate, with cells irregularly multilateral and cell margins undulate.

5.4.2 | Description

Shrubs, often straggly, 0.6–3 m tall; branches pendulous, terete, hispidulous or puberulent to glabrescent. Leaves simple, opposite, usually distichous, infrequently whorled of three or more on sterile shoots or at nodes, subsessile; leaf blade entire, papery, green above and pale green below in shady situations, or thickly papery, rugulose, dark green above when growing in open places or in thickets, ovate‐ lanceolate or ovate, 3.5–10 � 1.8–4 cm, adaxially glabrous to sparsely hispidulous, abaxially sparsely to moderately scaberulous or hispidulous with pubescence denser on principal veins, base rounded to cuneate, apex acute to weakly acuminate; secondary veins 4‐7 pairs; stipules caducous to persistent, entire, triangular, glabrescent, apex erect, cuspidate. Inflorescences axillary or pseudoterminal, (6‐) 8–25 cm long, long pyramidal in outline, paniculate with 3‐15 pairs of opposite decussate or ternate branches; lateral branches 1‐ 2 orders, basal branches 3–7 cm long, usually subtended by leaf‐ like bracts, decreasing in size distally, often reduced to deltoid scales 0.5–1.5 mm; rachis and branches densely hispidulous to puberulent, sessile and tripartite or pedunculate; axis not branched 2– 5 cm. Flowers shortly pedicellate. Calyx puberulent to glabrous; hypanthium ellipsoid to subglobose, 1.3–1.8 mm; limb deeply lobed; lobes lanceolate or triangular, 0.5–0.8 mm. Corolla greenish to reddish, tubular‐ funnelform, outside glabrous; tube inside pubescent in upper part; lobes oblong to elliptic. Anthers linear‐ oblong, partially exserted. Style coiled in the flower buds and pollens shed on the stigmas before anthesis. Stigmas clavate, upper surface concave when receptible. Ovary 2‐celled, ovules 10–15 in each cell on peltate axile placentas at the central of the axile. Capsules subglobose or ellipsoidal, 1.8–2.1 � 1.5–2.0 mm, calyx limbs persistent, glabrous or pilose, pericarps woody, open apically and dehiscent septicidally along the septa into two valves with valves later sometimes splitting loculicidally through the locule wall; seeds triangle to square pyramidal, or irregular in shape, often elongated, 1.0–1.5 � 0.3–0.5 mm, truncate at base and acute at the distal end, terminal hilum on the truncate base, unwinged, seeds brownish, surface alveolated‐ reticulated, testae reticulate, with cells irregularly multilateral and cell margins undulate.

5.4.3 | Distribution and habitat

Yunnan of China, Bhutan, India, Nepal, Thailand. In tropical or subtropical forests or in thickets; alt 200–1500 m.

5.4.4 | Representative specimens examined

CHINA: A. Henry No. 12878 ( K!); A. Henry No. 13227 ( K! US!); E. Liu No. 014 ( PE); H. Wang No. 6341 ( HITBC!); H. Wang No. 4317 ( HITBC!); G. Tao and X. Li No. 39462 ( HITBC!); X. Gao No. 333 ( KUN!); G. Tao No. 9061 ( KUN!); W. Yin No. 2005 ( KUN!); Y. Li No. 5981 ( KUN!); Y. Li No. 2070 ( KUN!); T. Zhu No. 640 ( IBSC!); T. Zhu No. 648 ( KUN!); Q. Wang No. 72841 ( IBSC!); S. Yuan No. 154 ( IBSC!); J. Cai No. 09 CS 1043 ( IBSC!); J. Cai No. 13 CS 5833 ( IBSC!); J. Yin No. 1997 ( HITBC!); J. Li No. 257( HITBC!); S. Zhou 14876 ( HITBC!); S. Zhou 14878 ( HITBC!); T. Tu No. 1143 ( IBSC!); T. Tu No. 1144 ( IBSC!); T. Tu No. 1145 ( IBSC!); L. Zhou No. 15399 ( IBSC!).

INDIA: N. L. Bor No. 25 ( K!); N. L. Bor No. 2834 ( K!); G. Watt No. 5111 ( K!); G. Watt No. 5069 ( K!); G. Watt No. 6671 ( K!); G. Watt No. 7214 ( K!).

NEPAL: Wall. Cat. No. 6275 ( BM!, K!, BR!) (type); Cai et al. No. QTP‐ II08‐ T05‐003166 ( KUN!) .

BHUTAN: W. R. Jacob No. 125 ( K!); G. L. Searight No. 283 ( K!); A. J. C. Grierson and D. G. Long No. 2983 ( K!); East Nepal Expedition No. 9240494 ( E!).

THAILAND: P. Pratoom et al. No. 131 ( QBG image!).