Senna neglecta (Vogel) H.S.Irwin & Barneby
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Authors
Howard S. Irwin, Rupert C. Barneby
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Authority
Irwin, Howard S. & Barneby, Rupert C. 1982. The American Cassiinae. A synoptical revision of Leguminosae tribe Cassieae subtrib Cassiinae in the New World. Mem. New York Bot. Gard. 35, part 1: 1-454.
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Family
Caesalpiniaceae
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Scientific Name
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Type
Typus infra sub var. neglecta indicatur.
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Synonyms
Cassia neglecta Vogel
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Description
Species Description - Weakly woody shrubs of straggling or bushy habit, malodorous when bruised, variably pubescent with loosely incurved or erect hairs up to 0.3-0.7 mm (the vesture more fully described under the vars.), the dull olivaceous bicolored leaflets either glabrous or puberulent above, densely pilose or glabrescent beneath, the inflorescence a rather dense, commonly narrow panicle of racemes often leafy-bracteate proximally but always, at least distally and often wholly, exserted from foliage. Stipules erect or patent, thinly herbaceous very early dry caducous, absent from many spms, in outline lanceolate, linear-lanceolate or lance-acuminate 2.5-10 x 0.4-2 mm. Lvs below (and often some at base of) panicle (6.5-)8-16(-17) cm; petiole including dilated but texturally little differentiated pulvinus 1.6-3(-3.5) cm, at middle 0.7-1.4 mm diam, bluntly carinate dorsally, grooved along either side of keel, openly shallow-sulcate ventrally; rachis 2.5-6.5 cm; petiolar gland 1 sessile at or up to 4-10 mm distant from the pulvinus, 2-12 mm distant from stem, obtusely mounded, inversely pyriform, globose or depressed-globose, usually as wide or wider than tall, in profile 0.6-2 mm tall, 1-2.5 mm diam, blackish and wrinkled when dry; lfts 4-5(-6) pairs, moderately or strongly accrescent distally, the ultimate pair subobliquely elliptic, obovate- or oblong-elliptic (3-)3.5-7.5(-9) x (1-) 1.2-2.4(-2.6) cm, 2.2-3.8(-4) times as long as wide, at apex either broadly or narrowly triangular-acute or (when relatively broad) obtuse- mucronulate, at base rounded or subcordate on proximal and cuneate on distal side, the margin commonly but not always revolute, the straight or slightly incurved midrib immersed or shallowly depressed on upper face, cariniform beneath, the 8-14(-16) pairs of major camptrodome (and random intercalary) secondary veins usually finely prominulous on upper and sharply so on lower face, the weak or sharply defined tertiary and quaternary venulation equally variable; short proximal lfts proportionately broader, the lowest pair often ovate; lvs in inflorescence mostly reduced to depauperate stalk with abortive blade but scarcely diminished gland. Racemes rather densely 7-30(-35)-fld, the expanded fls raised to or slightly beyond the nodding, obliquely ovoid or oblong-obovoid obtuse fl-buds, the axis including short peduncle becoming (1.5-)2.5-9.5 cm; bracts very early caducous, ovate or lance-acuminate 1.2-3.5 mm; mature pedicels 1-2.6 cm; sepals little graduated, the outer greenish or fuscous with paler margins, the inner subpetaloid, all oblong or obovate obtuse, the longest 5-11 mm; petals glabrous bright yellow, when dry tardily whitening and brown-veined, of ± equal length, the vexillary one obovate or obovate- to cuneate-flabellate 4.5-8 mm wide, the rest more narrowly obovate or oblanceolate 2.5-5.5 mm wide, the longest 9-19 mm, the abaxial pair almost always oblanceolate, one of them nidulating the pistil; androecium glabrous, the 3 staminodes 0.9-1.3 mm wide, the filaments of 4 median stamens 1.2-2.3 mm, of 2 long abaxial ones 5-7 mm, of the centric abaxial one 1.5-3.5 mm, the anthers of 4 median stamens 3.1-5 x 0.8-1.2 mm, of 2 long abaxial ones (4.2-)4.5-6(-7) x 1.2-1.5 mm, of the centric abaxial one sterile linear 1.5-5 x 0.2-0.5 mm, the fertile anthers all constricted distally and then obliquely dilated, the orifice of the long ones produced on abaxial side beyond the two pores into a pollen-cup 0.3-0.6 mm; ovary strigulose, pilosulous or rarely glabrate; style 3-5.5 mm, sulcate on the inner side, abruptly thickened and strongly incurved at apex, there 0.3-0.5 mm diam, the introrse stigmatic cavity pilosulous and apparently often viscid; ovules 32-48. Pod erratically spreading-pendulous, the true stipe 2-5 mm cuneately expanded into the linear piano-compressed body, this (6.5-)8-19 x 0.75-1.4 cm, stoutly carinate by the sutures, the papery greenish, later brown paler-margined valves scarcely raised over the seeds, early glabrate, faintly or prominulously venulose; seeds (poorly known) oblong, moderately compressed parallel to the valves, 4.5-7 x 2-3.5 mm, the ochraceous- or castaneous-brown, scarcely lustrous or dull testa either smooth or pitted, the areole 2.6-4.5 x 1-1.5 mm.—Fig. 1 (petiolar nectary).
Variety Key - Key to the Varieties of S. neglecta 1. Fls small, the longer sepals 5-7.5(-8) mm, the longest petal 9-13 mm. 2. Lower face of lfts pilosulous overall, the upper face nearly always puberulent, exceptionally glabrate, the margin in any case revolute; s.-e. Brazil, s.-ward from Parana, and apparently locally disjunct in s. Espirito Santo; stipules 2.5-4.5 mm. 137a. var. neglecta (p. 423). 2. Lower face of lfts pilosulous only in distal basal angle of midrib, the upper face glabrous, the margin plane; local in Rio de Janeiro (Sa. dos Orgaos) and Minas Gerais (Sa. da Caraga); stipules 5-9 mm. 137c. var. oligophylla (p. 424). 1. Fls larger, the longer sepals 8.5-11 mm, the longst petal 14-19 mm. 3. Lower face of lfts pilosulous overall; pod ±8-10 mm wide; n.-e. Minas Gerais and s.-e. Bahia. 137b. var. grandiflora (p. 423). 3. Lower face of lfts pilosulous only in distal basal angle of midrib; pod ± 14 mm wide; s. Espirito Santo (Furno Grande). 137d. var. furnicola (p. 425).
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Discussion
In characters of foliage S. neglecta stands intermediate between S. cernua and S. hirsuta, combining the essentially oblong-elliptic or oblanceolate leaflet-outline of the former with the relatively few (4-5) pairs of the latter. Furthermore the anterior lip of the pore of the long anthers is intermediate in length. Its range is largely extratropical and lies mostly to the east and south of these kindred species; where it extends north of the tropic line it is almost confined to the Atlantic slope and is substantially sympatric only with S. hirsuta var. streptocarpa. Some forms of S. neglecta closely simulate the paucifoliolate varieties of Caribbean S. mexicana, and such is the degree of internal variation in both these species that differential characters consistently applicable to all individuals of each are hard to find. Generally speaking, S. mexicana, when agreeing with S. neglecta in leaflet number, has smaller leaflets, a narrower pod containing smaller seeds (about 3^.5, not 4.5-7 mm long) marked with smaller areoles 1.2-2.4, not 2.6-4.5 mm long), and a rather shorter style (2-3, not 3-5.5 mm long). The petiolar gland of S. neglecta is situated either next to the pulvinus, like that of S. hirsuta, or on the petiole up to 1 cm distant from it, when it simulates that of S. mexicana. All of these four species form a complex series of mostly vicariant Basiglandulosae in which a few variable features appear in various combinations almost throughout the American tropics. Interrelationships in the group are often perplexing and more than one rational taxonomic scheme could be contrived to express them. Key to the Varieties of S. neglecta 1. Fls small, the longer sepals 5-7.5(-8) mm, the longest petal 9-13 mm. 2. Lower face of lfts pilosulous overall, the upper face nearly always puberulent, exceptionally glabrate, the margin in any case revolute; s.-e. Brazil, s.-ward from Parana, and apparently locally disjunct in s. Espirito Santo; stipules 2.5-4.5 mm. 137a. var. neglecta (p. 423). 2. Lower face of lfts pilosulous only in distal basal angle of midrib, the upper face glabrous, the margin plane; local in Rio de Janeiro (Sa. dos Orgaos) and Minas Gerais (Sa. da Caraga); stipules 5-9 mm. 137c. var. oligophylla (p. 424). 1. Fls larger, the longer sepals 8.5-11 mm, the longst petal 14-19 mm. 3. Lower face of lfts pilosulous overall; pod ±8-10 mm wide; n.-e. Minas Gerais and s.-e. Bahia. 137b. var. grandiflora (p. 423). 3. Lower face of lfts pilosulous only in distal basal angle of midrib; pod ± 14 mm wide; s. Espirito Santo (Furno Grande). 137d. var. furnicola (p. 425).