NOVON 7(4): 350-352. 1997.
Herbarium, South China Institute of Botany, Chinese Academy of Sciences, Guangzhou, Guangdong 510650, People’s Republic of China
Department of Forestry, Zhejiang Forestry College, Linan, Zhejiang 311300, People’s Republic of China
ABSTRACT. The new species Sinojackia microcarpa C. T. Chen & G. Y. Li is described and illustrated, and the characters distinguishing it from the related species S. rehderiana are given.
Sinojackia Hu is a Chinese endemic genus of about five species. It was described by Hu (1928) based on S. xylocarpa, which was collected from Jiangsu. Hu (1930) added S. rehderiana from Jiangxi, Merrill (1937) transferred Pterostyrax henri to Sinojackia, Qi (1981) described S. dolichocarpa from Hunan, and Luo (1992) described S. sarcocarpa from Sichuan. Chen (1995) transferred S. dolichocarpa to the monotypic Changiostyrax because it has an unarmed trunk, scaly buds, 4-merous, ebracteate flowers, a truncate calyx tube, 8 equal stamens, anthers without prolonged connectives, and other features not found in Sinojackia. The following new species was discovered in Zhejiang Province during recent field surveys in connection with studies on the phytogeography of Styracaceae.
Sinojackia microcarpa C. T. Chen & G. Y. Li, sp. nov. TYPE: China. Zhejiang: Jiangde Co., Meicheng, Wushitan, bushes along stream, 40 m, ca. 29.5 N, 119.5 E, 6 Nov. 1995, C. T. Chen 9511041 (holotype, IBSC; isotype, MO). Figures 1--12.
Species S. rehderianae Hu simillima, sed fructu parviore, 3--4 mm diametro, leviter 6--12-costato, mesocarpio neque incrassato neque suberoso differt.
Shrubs deciduous, to 3 m high; trunk thorny, 2--4 cm DBH; bark grayish brown, longitudinally fissured. Current year’s shoots green, densely stellate pubescent, second year’s branches blackish brown, glabrous, longitudinally striate, bark vertically fissured and peeling off. Buds with orbicular green scales, densely stellate pubescent. Leaves alternate, simple, papery; petiole 3--4 mm long; blade ovate to elliptic, 6--12 cm long, 2.5--6 cm wide, apex acuminate, base broadly cuneate or rounded, margins remotely glandular-serrulate, with 8--10 lateral veins on each side of midrib; young leaves sparsely stellate-pubescent abaxially and along veins adaxially, glabrescent, prominently and closely reticulate adaxially, smoother and more shiny green abaxially. Inflorescences densely racemose, 3--7-flowered, 4--8 cm long, produced laterally at nodes on second year’s branches; rachis and pedicels slender, densely stellate-pubescent; pedicels 3--17 mm long. Flowers bisexual, ± pendulous, stellate-pubescent on most parts except style, the basal 1--3 in each inflorescence subtended by a leafy bract; bracts with petiole 1--2 mm long, blade 2.5--5 cm long, base rounded to subcordate; uppermost flowers with a small lanceolate bract adnate to pedicel, rarely ebracteate. Calyx (5)6(7)-dentate; teeth triangular, 1--2 mm long, 0.8--1 mm wide at base. Corolla white, deeply 6(7)-parted; lobes imbricate, oblong-lanceolate, 7--8 mm long, 2--3 mm wide, curved at apex. Stamens 12(--14), unequal, free portion 5--6 mm long; filaments curved, slightly arcuate, united at base; anthers oblong, longitudinally dehiscent, connective shortly produced. Ovary inferior, 3-locular; ovules 4--8 in each locule, biseriate; style terminal, slender, glabrous, 5--8 mm long; stigma obscurely 3-lobed. Fruit indehiscent, fusiform, grayish brown, 6--12-ribbed when dry, 1.5--2 cm long, 3--4 mm diam., tapered at base, apex subulate, beaked, the beak 0.5--1 cm long; exocarp thin, sparsely stellate pubescent; mesocarp undeveloped; endocarp thin, bony; seed solitary, ca. 1 cm long; seed coat smooth. Fruiting pedicel 0.5--2 cm long.
Sinojackia microcarpa is similar to S. rehderiana Hu in fruit morphology, but differs in having smaller fruit 3--4 mm in diameter, 6--12-ribbed when dry, and in lacking the mesocarp. In contrast, S. rehderiana has larger (5.5--6 mm diam.), unribbed fruit with thickened, corky mesocarp.
Sinojackia microcarpa is the first representative of Sinojackia recorded from Zhejiang Province. It is a very rare species confined to stream sides in a small valley at altitudes of 25--200 m. Its white and showy flowers should be of ornamental value. Mature seeds are eaten by birds.
Paratypes. CHINA. Zhejiang: Jiangde Co., bushes along stream, 30 m, 10 May 1995, C. T. Chen 9505033 (IBSC, MO), 25 m, 4 Apr. 1989, G. Y. Li et al. 0155 (ZJFC), 40 m, 28 Aug. 1989, G. Y. Li et al. 0158 (ZJFC), 40 m, 4 Oct. 1989, L. Din & M. Wang 0172 (ZJFC).
Acknowledgments. This work was supported by a grant in Aid No. 930136 to Chen Tao from the Chinese Academy of Sciences. We are grateful to Peter H. Raven (MO) for his continuous encouragement, and to Hu Chiming (IBSC) and Ihsan Al-Shehbaz (MO) for their support and comments on the manuscript.
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