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Systematics of south american tripsacum gramineae

, : Systematics of south american tripsacum gramineae. American Journal of Botany 68(2): 269-276

Tripsacum is widely distributed between and In South America the genus extends around the Amazon and Orinoco basin, and from the Caribbean coast south to Brazil and Paraguay. The most common South American taxon is T. dactyloides (L.) L. var. meridonale de Wet and Timothy (2n = 36), which differs from North American representatives of the species in having subdigitate racemes usually appressed with the apical male sections typically curved. Closely related to T. dactyloides, but occupying more seasonally moist and dry habitats, is T. australe Cutler and Anderson. This species is robust with the basal leaf sheaths tomentose and the much elongated culms becoming decumbent in older plants. Smaller plants, with essentially erect culms and leaf sheaths on the culms hirsute rather than tomentose, are recognized as T. australe var. hirsutum de Wet and Timothy. The 2 varieties of T. australe are both diploid (2n = 36) and cross to produce fertile hybrids. They also cross with T. dactyloides var. meridonale (2n = 36), but these hybrids are partially sterile. T. cundinamarce de Wet and Timothy (2n = 36) is a robust species with glaucus leaves. It resembles robust specimens of T. dactyloides in having glabrous leaf sheaths, but can always be recognized by inflorescences that are composed of racemes arranged along a several-noded primary axis. This species is confined to moist habitats, while T. dactyloides occupies a range of habitats in South America. T. peruvianum de Wet and Timothy is a gametophytic apomict with 2n = 72, 90 or 108 chromosomes. It is characterized by an erect growth habit and strongly hirsute leaf sheaths. The cultivated Guatemala grass, T. andersonii Gray, occurs spontaneously in the mountains of Venezuela, Colombia and Peru. This sexually sterile species is characterized by 2n = 64, and may combine 54 Tripsacum and 10 Zea chromosomes in its genome. Electrophoretic patterns of seed storage proteins confirm the validity of recognizing T. cundinamarce as distinct from T. dactyloides and T. peruvianum as distinct from T. australe.

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Accession: 006574657

DOI: 10.2307/2442859

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Related references

Fletcher, G.B., 1982: Systematics and biogeography of South American Tripsacum. The geographical distribution of members of the genus Tripsacum and the likely evolutionary spread of the genus from origins in India are described. The chromosome numbers of several spp. are given.

Wet, J.M.J. de; Gray, J.R.; Harlan, J.R., 1976: Systematics of Tripsacum (Gramineae). Herbarium specimens, living plants grown in uniform nurseries and naturally occurring populations across the range of Tripsacum in North and South America were studied. The genus is composed of two species complexes. The following species have pen...

Dewet J.M.J.; Harlan J.R.; Brink D.E., 1982: Systematics of tripsacum dactyloides gramineae. T. dactyloides (L.) L. extends across the range of this genus from about to latitude in the New World. It is recognized to include T. dactyloides var. dactyloides (North America), T. d. var. meridonale deWet et Timothy (Sou...

Dewet, J.; Harlan, J.1; Brink, D., 1982: Systematics of Tripsacum dactyloides (Gramineae) New taxa. American journal of botany 69(8): 1251-1257

D.W.t J.M.J.; Brink D.E.; Cohen C.E., 1983: Systematics of tripsacum section fasciculata gramineae. Tripsacum sect. Fasciculata is characterized by staminate spikelet pairs in which 1 spikelet is sessile and the other is supported by a long and slender pedicel. In sect. Tripsacum both spikelets of a staminate pair are sessile, or one is supporte...

De-Wet, J.; Brink, D.1; Cohen, C., 1983: Systematics of Tripsacum section Fasciculata (Gramineae) New taxa. American journal of botany 70(8): 1139-1146

Mueller, C., 1983: Studies on south american gramineae 1. 2 new varieties of south american chloris species. Two new varieties of South American Chloris spp. are described: C. radiata (L.) Sw. var. longiaristata and C. halophila Parodi var. humilis.

Parodi, L.R., 1942: A new South American species of the Maydeae, genus Tripsacum. On account of the botanic and genetic interest-due to its phylogenetic connexion with maize-of Tripsacum australe, a new South American species described by H. C. Cutler and E. Anderson (see Herb. Abstr. 12. Abs. 522.

Muller, C., 1985: South American Gramineae. II. Keys for determination of Chloris species of South America. Feddes Repertorium6(4): 269-277

Muller, C., 1985: Studies on the South American Gramineae II. A key to Chloris species of South America. An annotated key to S. American Chloris spp. is presented. The 1st records of a number of spp., including C. gayana, in Bolivia, Ecuador and Brazil are also reported.