On Systematic Position of Pterygocalyx (Gentianaceae)

Abstract

Abstract:

The gross morphology, floral anatomy, embryology, pollen and karyotypes of

Pterygocalyx volubilis were studied. The results are used to reevaluate the taxonomic status

of the monotypic genus Pterygocalyx. Pterygocalyx volubilis has epipetalous glands. There

are 16 bundles in calyx tube and 12 bundles in corolla tube, the calyx and corolla bundles are

different in origin. Each carpel has one dorsal and two ventral bundles. Flowers are protan-

drous. The anther is 4-sporangiate. The development of anther walls conforms to the di-

cotylendonous type . The tapetum is of glandular type, dual origin, and binucleate cells at the

late stage. The epidermis and part of endothecium persist; epidermisis fibrous-thickened.

Cytokinesis in the microsporocyte meiosis is simultaneous, and tetrads are tetrahedral. Pollen

grains shed at the 3-celled condition. The ovary is bicarpellate and unilocular. The placenta-

tion is of superficial placentae with 25～40 series of ovules. The ovule is unitegmic, tenuinu-

cellar and anatropous. The embryo sac originates from a single archesporial cell. The chalazal

megaspore in linear tetrad becomes the functional one. The development of embryo sac is of

the Polygonum type. Before fertilization, two polar nuclei fuse into a secondary nucleus.

Three antipodals persist, become much enlarged, and function as haustorium. The develop-

ment of the endosperm is of the Nuclear type. Pollen grains of Pterygocalyx are spheroidal,

32.8×34.2 μm in size with exine ornamentation being reticulate. The chromosome number

of Pterygocalyx is 2n＝26, with the basic number x＝13. The karyotype is formulated as 2n

=26＝8m+4sm+2st+2t, belonging to “2A” type in Stebbins'classification. The genus

Pterygocalyx is closely related to Gentianopsis . It is better to treat Pterygocalyx as an in-

dependent genus.

Key words: Pterygocalyx, Systematic position

CHEN Shi-Long, HO Ting-Nong, HONG De-Yuan. On Systematic Position of Pterygocalyx (Gentianaceae)[J]. .

[1]	ZHOU Qi-Xing, GU Zhi-Jian, YUE Zhong-Shu. Karyomorphology and relationships of Amentotaxus Pilg. [J]. , 2000, 38(6): 522-527.
[2]	YANG Qin-Er. Correction of karyotype of diploid Beesia calthifolia and discovery of a tetraploid cytotype [J]. , 1999, 37(1): 1-9.
[3]	Han Li-juan, Hu Yu-shi, Lin Jin-xing. Anatomy of Secondary Phloem of Glyptostrobus in Relation to Its Systematic Position [J]. , 1997, 35(6): 527-532.
[4]	Kong Hong-zhi, Yang Qin-er. Karyomorphology and Relationships of the Genus Circaeaster Maxim. [J]. , 1997, 35(6): 494-499.
[5]	Tang Ya. On the Systematic Position of Paradombeya Stapf [J]. , 1993, 31(4): 297-308.
[6]	Zhang Zhi-Yu, Lu An-Ming, Pan Kai-Yu, Wen Jie. The Anatomy, Embryology and Systematic Relationships of Eucommiaceae [J]. , 1990, 28(6): 430-441.
[7]	Ma Yu-Chuan, Zhang Shou-Zhou. Study on the Systematic Position of Tetraena Maxim [J]. , 1990, 28(2): 89-95.
[8]	Hu Yu-Shi, Ma Rui-Jun. Anatomy of Gymnosperms Endemic to China, II. Taiwania flousiana Gaussen (Taxodiaceae) [J]. , 1989, 27(2): 96-104.
[9]	Zhang Zhi-Yun, Lu An-Ming. On the Systematic Position of Daphniphyllaceae [J]. , 1989, 27(1): 17-26.
[10]	Ruan Yun-Zhen. Notes on the Genus Prismatomeris Thw. (Rubiaceae) of China [J]. , 1988, 26(6): 443-449.
[11]	Chu Ge-Lin. On Systematic Position of Baolia Kung et G. L. Chu in Chenopodiaceae [J]. , 1988, 26(4): 299-300.
[12]	Zhang Zhi-Yu. A Study on the Pollen Morphology of Actinidiaceae and Its Systematic Position [J]. , 1987, 25(1): 9-23.
[13]	Hu Zhi-Ang, Wang Hong-Xin, Liu Chang-Jiang, Qian Zhong-Xing. Biochemical Systematics of Gymnosperms (3)—On the Systematic Position of Tax aceae from Their Seed Protein Peptides and Needle Peroxidases [J]. , 1986, 24(4): 260-263.
[14]	Lan Yang-Zhen. Chromosome Numbers of Brassiceae (Cruciferae) in China [J]. , 1986, 24(4): 268-272.
[15]	long huo,He Li-King, Hsue Hsiang-Hao. Pollen Morphology of Craigia with Reference to Its Systematic Position [J]. , 1985, 23(3): 179-184.

On Systematic Position of Pterygocalyx (Gentianaceae)

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