Cassia fagonioides Vogel var. fagonioides

Authors

Howard S. Irwin, Rupert C. Barneby

Authority

Irwin, Howard S. & Barneby, Rupert C. 1978. Monographic studies in Cassia (Leguminosae, Caesalpinioideae). III. Sections Absus and Grimaldia. Mem. New York Bot. Gard. 30: 1-300.

Family

Caesalpiniaceae

Scientific Name

Cassia fagonioides Vogel var. fagonioides

Type

Holotypus, presumably †B, not seen; neoholotypus, Sello s.n., K! = IPA Neg. 1015 = NY Neg. 1477; isotypi, BM = NY Neg. 6762, F, G, LE, P! — C. hispidula var. fagonioides (Vogel) Bentham in Mart., Fl. Bras. 15 (2): 131. 1870. Grimaldia fagonioides (Vogel)

Synonyms

Grimaldia fagonioides (Vogel) Pittier, Cassia fagonioides Vogel, Cassia hispidula var. fagonioides (Vogel) Benth., Cassia killipii Rose, Grimaldia killipii (Rose) Britton & Rose, Cassia hispidula var. killipii (Rose) Schery, Grimaldia decora Britton & Rose, Cassia tetraphylla Desv., Grimaldia baileyorum Britton & Rose

Description

Species Description - Stems usually less than 1 m; lfts commonly small, the largest of a given plant 8-14 (-16), in s.-centr. Minas Gerais up to 13-20 mm; fls relatively small (as in key); pod (2-) 2.5-3.5 x (4.5-)5-7 mm, hispid with setae up to (2-)2.5-5 mm. — Collections: 64.

Distribution and Ecology - Savannas and open grassy places in pine-forest (British Honduras), restinga (Bahia), or campo (Minas Gerais), widely but discontinuously dispersed, mostly below 300 m, around the n. and e. coasts of South America from Espfrito Santo, Brazil, to Panama, inland in the lower Amazon valley in Para (to Prainha and Montealegre), to the Pakaraima Mts (at ± 10001200 m) in Guyana, and to the lower Orinoco Valley in Venezuela (edos. Monagas, Bortvar, Anzoategui), unknown from Trinidad or Colombia, in s.-e. Brazil extending inland and up to 1200 m in s.-centr. Minas Gerais (Belo Horizonte s. to n. slope of Sa. da Mantiqueira); apparently disjunct on Pacific slope of Nicaragua (prov. Chinandega) and s. Mexico (Guerrero) and on Gulf slope in lowland British Honduras and the Usumacinta valley along the Chiapas-Peten boundary. - Fl. almost throughout the year.

Discussion

A degree of polymorphism within var. fagonioides reflects its discontinuous dispersal through about 38 degrees of latitude (17° N to 21° S). The commonest form, prevalent everywhere between coastal Espfrito Santo and Panama, has small leaflets variable in pubescence combined with a flower with four relatively long, slenderly clawed, spatulate or oblanceolate petals about 9-13 mm long. At either end of the range, in British Honduras and in southern Minas Gerais, the variety is represented by small-flowered races, in which the longer petals are proportionately broader, shorter-clawed, and only 7-8.5 mm long. The first of these has the small leaflets of the most widespread type; the latter ample leaflets like those prevalent in var. macrocalyx. However, small- and large-flowered plants have been collected together on the savannas of the Orinoco in Venezuela (McKee 10767, 10777) and in the same region there occur populations in which the larger flower is combined with either small or larger leaflets (Pittier 14470, 14539). Geographic differentiation seems to be actively underway within var. fagonioides, but has not reached the point at which taxonomic recognition becomes pressing. The idealized differences may be summarized in key form:

a. Longest petals 9—13 mm, narrowed to a slender claw ± 2 mm, Esplrito Santo to Panama, perhaps Pacific slope of Nicaragua, s.-w. Mexico (Guerrero).

a. Longest petals 6.7—8.5 mm, contracted to a short broad claw ± 1 mm;

b. Larger leaflets up to 13—20 mm; southernmost Sa. do Espinhajo s. to n. slope of Sa. da Mantiqueira in Minas Gerais.

b. Larger petals 8-12 mm; British Honduras and adjoining Usumacinta valley in Mexico (presumably also Peten, Guatemala)

The types of C. killipii, Grimaldia decora, and G. baileyorum all represent the commonest variant with relatively small leaflets and large flowers.

The occurrence of var. fagonioides on the Pacific coast of Mexico is poorly documented by two mixed collections. Langlasse 515 (G) and Palmer 501 (type of Grimaldia decora), from near Petatlan and Acapulco, Guerrero, the mixture in each case involving an element of C. tetraphylla. These two species are often sympatric southward, and there is no real reason to doubt their existence together in Mexico even though the nearest known station for C. fagonioides on the western slope is in Nicaragua. We follow Amshoff (1939, p. 24) in listing Grimaldia decora and G. killipii as synonyms of var. fagonioides.

Distribution

Honduras Central America| Bahia Brazil South America| Minas Gerais Brazil South America| Espirito Santo Brazil South America| Panama Central America| Pará Brazil South America| Guyana South America| Venezuela South America| Monagas Venezuela South America| Bolívar Venezuela South America| Anzoátegui Venezuela South America| Trinidad and Tobago South America| Colombia South America| Nicaragua Central America| Chinandega Nicaragua Central America| Guerrero Mexico North America| Chiapas Mexico North America| Petén Guatemala Central America| Guatemala Central America| Veracruz Mexico North America|