2. 中国科学院核心植物园保护生物学中心, 广州 510650;
3. 仲恺农业工程学院, 广州 510225;
4. 台城镇, 广东 台山 529200;
5. 广海中学, 广东 台山 529231
2. Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou 510650, China;
3. Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China;
4. Taicheng Town, Taishan 529200, Guangdong, China;
5. Guanghai Middle School, Taishan 529231, Guangdong, China
The genus Michelia L., with ca. 70 species, mainly occurs in India, Sri Lanka, China, Indochina, Malaysia and South Japan[1–4]. As one of the centers of modern distribution and diversity of the genus, China harbors 39 or 37 species of Michelia including one or two hybrid species.
During a recent field trip to Beifeng Mountain in Guangdong, China, an interesting species of Michelia with slender petioles and white flowers with numerous stamens draw our attention. At first glance, it seems much like M. guangdongensis Y. H. Yan, Q. W. Zeng & F. W. Xing in having obovate white tepals and hairy leaf blades (at least when young). However, the abaxial surface of leaf blade of this unknown species is reddish brown sericeous only when young and becomes glabrous soon, while M. guangdongensis has leaf blades with persistent dense rufous hairs on abaxial surface. After a detailed examination of morphological characters of this unknown species, we concluded that it is new to science, as described and illustrated below.
Type: China. Guangdong Province: Taishan City, Beifeng Mountain, Sanyashi, elev. 792 m, Taishan Expedition 440181190321027LY (holotype IBSC, iso- types IBSC).
Diagnosis: Similar to M. guangdongensis, but differs by its more slender petiole, leaf blades with glabrescent abaxial surface and much more and longer stamens with white filaments and much shorter anther connectives.
Evergreen trees or shrubs, to 6 m tall, to 20 cm DBH. Bark grayish white. Young twigs and buds densely reddish brown sericeous. Petiole slender, 1.5– 2.5 cm×ca. 0.15 cm, adaxially narrowly furrowed, without a stipular scar, reddish brown sericeous when young, glabrescent when old; leaf blade obovate, elliptic-obovate or oblong-obovate, 5.5–10.7 cm×3.0– 4.7 cm, leathery, reddish brown sericeous on both sides when young, glabrescent when old, secondary veins 7–10 pairs, slender, anastomosing near the margins, with reticulate veins prominent on both sides, reticulate veins slender, forming a honeycomb pattern, base cuneate to broadly cuneate, apex shortly acumi- nate. Brachyblasts 1.1–2.3 cm×0.3–0.4 cm, initially reddish brown sericeous, glabrescent; spathaceous bract 1, reddish brown sericeous. Flower buds obovoid to ellipsoid, apex acute. Tepals (8–)9(–10), white, base slightly greenish abaxially, glabrous, outer 3 tepals broadly obovate to obovate-elliptic 4.0–6.3 cm× 2.6–3.2 cm; middle 3 obovate-elliptic, 4.4–6.2 cm× 2.6–3.0 cm; inner (2–)3(–4) elliptic, 2.9–4.6 cm× 1.6–2.3 cm. Stamens 77–100, 2.0–2.3 cm long; filaments flat, white, ca. 5 mm long; anthers slightly incurved, yellowish, 1.4–1.7 cm long; connective mucronate, mucro triangular, ca. 0.2 mm long. Gyno- phore green, terete, 0.8–1 cm long, together with gynoecium green sericeous when fresh, reddish brown when dry; gynoecium 1.8–2 cm long; carpels 21–25; ovules 4–6 per carpel; style yellowish-green, recurved, 1–1.4 mm long. Fruit 6.5–10 cm long; mature carpels ellipsoid to ovoid, 0.8–1.5 cm×ca. 1 cm, scattered with white lenticels externally, apex with a short tip. Seeds pink, ovoid or subglobose, slightly angled.
Phenology: Flowering from March to April, fruiting from August to September.
Distribution and habitat: Michelia taishanensis is currently known only from the type locality, Bei- feng Mountain in Taishan City of Guangdong Province. It grows in montane forest at the mountain top at elevations of 740–800 m. The companion species includes Metasasa carinata W. T. Lin, Rapanea nerii- folia (Siebold et Zucc.) Mez, Symplocos lancifolia Sieb. et Zucc. and so on.
Etymology: The species epithet refers to the type locality, Taishan City.
Chinese vernacular name: 台山含笑(tái shān hán xiào).
Taxonomic notes: Michelia taishanensis is assigned to M. subg. Michelia sect. Michelia according to Xia's classification, as it has fleshy tepals with outer ones larger and long petiole (> 5 mm long) without a stipular scar. It is most similar to M. guang- dongensis, but differs from the latter by its more slender petioles (15–25 mm×ca. 1.5 mm vs. 5–15 mm× 1.8–2.2 mm), leaf blades with glabrescent abaxial surface (vs. persistently reddish brown sericous) and more and longer stamens (77–100 vs. 50–70 in number, 2.0–2.3 cm vs. 1.1–1.5 cm) with white filaments (vs. purplish red) and much shorter anther connectives (ca. 0.2 mm vs. ca. 1 mm).
Additional specimens examined (paratypes): China, Guangdong: Taishan City, Beifeng Mountain, 22 August 2018, N. H. Xia et al. TYH-1720 (IBSC).
Acknowledgments Mr. Wang Gang-tao from Hangzhou Xingse Technology Co. LTD is thanked for providing good photos. Our thanks also go to the staffs in Beifeng Mountain National Forest Park for their kind help during our field trip.
Law Y H, Xia N H, Yang H Q. The origin, evolution and phyto-geography of Magnoliaceae[J]. J Trop Subtrop Bot, 1995, 3(4): 1-12.
Xia N H, Law Y W, Nooteboom H P. Magnoliaceae[M]//Wu Z Y, Raven P H. Flora of China, Volume 7. Beijing: Science Press & St. Louis: Missouri Botanical Garden Press, 2008: 48-91.
Law Y W. Magnoliaceae[M]//Law Y W. Flora Reipublicae Popu-laris Sinicae, Tomus 30(1). Beijing: Science Press, 1996: 151-191. (in Chinese)
Xia N H. Taxonomic revision on the family Magnoliaceae from China[D]. Kunming: Kunming Institute of Botany, Chinese Academy of Sciences, 2007: 371.
Yan Y H, Zeng Q W, Xing F W. Michelia guangdongensis (Magnoliaceae), a new species from China[J]. Ann Bot Fenn, 2004, 41: 491-493.