Senna atomaria
Senna obtusifolia
flor de San Jose, flor de san josé, palo zorillo
blunt leafed senna, Chinese senna, Java-bean, sickle-pod wild senna, sicklepod
5–55-flowered, not spikelike;
bracts early caducous, to 5 mm.
usually 1 or 2(or 3)-flowered;
bracts caducous.
13–28 mm.
7–28 mm.
asymmetric, enantiostylous;
calyx greenish to yellow;
corolla yellow-orange, slightly dark-veined, longest petal 12–23 mm, highly asymmetric, 1 or both lower petals highly modified, strongly concave and folded over stamens (flag-shaped);
androecium slightly heterantherous, stamens 7 (similar in shape and size, abaxial ones slightly longer), staminodes 3;
anthers 2.8–5 mm, dehiscing by 2 short slits, apical appendage 0;
gynoecium incurved, ovules 46–70;
ovary glabrate, sometimes becoming hairy after fertilization;
style stout.
asymmetric, enantiostylous;
calyx pale green;
corolla pale yellow, longest petal 9–15 mm, 1 lower petal conspicuously larger;
androecium heterantherous, stamens 7, middle stamens 1/2 as long as abaxial or smaller, staminodes 3;
anthers of middle stamens 1–2.8 mm, of abaxial stamens 2–5 mm, dehiscing by U-shaped slit, apical appendage inconspicuous, cupped;
gynoecium incurved, ovules 16–38;
ovary hairy;
style incurved.
pendulous, flat, straight, 220–370 × 80–140 mm, woody, indehiscent or splitting transversely into woody segments.
erect or curved downward, flat, straight, 60–180 × 2.5–6 mm, faintly corrugated over seeds, indehiscent.
reddish brown, obovoid to oblong-obovoid.
dark reddish brown, rhomboid or subcylindroid-oblong.
= 24, 26, 28.
Senna atomaria
Senna obtusifolia
As with other trees from deciduous and semi-deciduous vegetation, Senna atomaria is covered with flowers before developing the foliage (H. S. Irwin and R. C. Barneby 1982). In the flora area, it occurs naturalized only very locally in Collier County (R. P. Wunderlin et al., http://florida.plantatlas.usf.edu/).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Senna obtusifolia is one of the most widespread weedy sennas native to the Americas (H. S. Irwin and R. C. Barneby 1982) and is probably naturalized circumtropically. The species is considered a noxious weed in many countries, posing problems especially for agriculture; it is able to completely invade pastures by dominating grass species, it strongly competes with crops, affecting yields negatively, and, although generally unpalatable to stock, if eaten, it is toxic to cattle. For these reasons, in Australia S. obtusifolia is designated as potentially of national concern, and authorities estimate that this invader can lead properties to become unproductive (Weeds of Australia, www.environment.gov.au/cgi-bin/biodiversity/invasive/weeds/weedsearch.pl; Land Protection, www.nrw.qld.gov.au/factsheets/pdf/pest/pp18.pdf). In the flora area, its range of distribution appears to have expanded from five southern and southeastern states in the early 1980s (Florida, Kentucky, Missouri, Texas, and Virginia; Irwin and Barneby) to currently almost half of the states. Although a few specimens were collected as far north as Nebraska and Wisconsin, it is not known to be established in those states.
Senna tora (Linnaeus) Roxburgh (Cassia tora Linnaeus) is sometimes considered synonymous with S. obtusifolia. However, due to differences in length and curvature of the fruit and in length of the petiole and pedicel, B. R. Randell and B. A. Barlow (1998) considered it distinct. H. S. Irwin and R. C. Barneby (1982) observed a range rather than distinct categories in the measures and shapes of these traits, and only molecular phylogenetic and biogeographic studies accompanied by morphometric analyses may definitively solve this taxonomic dilemma.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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