Cassia neesiana

Title

Cassia neesiana

Authors

Howard S. Irwin, Rupert C. Barneby

Scientific Name

Cassia neesiana Mart. ex Benth.

Description

58.  Cassia neesiana Martius ex Bentham in Martius, Fl. Bras. 15 (2): 148. 1870. — Typus infra sub var. neesiana indicatur.

Erect, diffuse, or sometimes humifuse subshrubs with few or several brittle stems arising annually from a xylopodium, 3-10 dm, the young stems, lf-stalks and inflorescences densely glandular-villosulous and weakly hispidulous with yellow (rarely reddish) setules, the concolorous foliage viscid, either pubescent like the stem but more thinly so, or simply villosulous, or simply setulose, exceptionally almost or truly glabrous, the inflorescence highly variable, immersed or exserted.

Stipules subulate-setacous, 1-3(-4, exceptionally -8) mm, becoming dry and tardily deciduous.

Lvs (3-)4.5-12(-13) cm, ascending and arcuately spreading, shortly petioled; pulvinus slightly dilated and discolored, 1-2 mm; petiole slender, (0.5-)0.6-2 cm, narrowly sulcate ventrally; rachis 2-9(-11) cm; lfts (5-)8-18(-21) in some larger leaves at least 10 pairs, mostly tilted forward and on edge from rachis on petiolule ± 0.5-0.7 mm, commonly imbricate when pressed, slightly decrescent upward, in outline lance-oblong to lance-elliptic, obtuse, subacute, or obscurely emarginate, usually mucronulate by the excurrent costa, 7-26 x (2-)2.5-6(-7) mm, at base strongly asymmetric, cordate on both sides or rounded proximally, the margins entire, plane or almost so, the blades firmly membranous, brownish-olivaceous, not or scarcely lustrous, the pubescence variable, the margins almost always either ciliolate or setulose or both, the faces glabrous or finely villosulous, the lower one sometimes also sparsely setulose or resin-dotted, the venation above immersed, beneath at least the costa and often i 3 pairs of secondaries prominulous.

Racemes commonly 7-20-fld becoming 3-9 cm, exceptionally longer, usually 2-several on each major branchlet, terminal to this (when sometimes appearing leaf-opposed) or terminal to axillary branchlets, or sessile in a lf-axil, the lvs sometimes abruptly reduced beyond the first raceme and the inflorescence then paniculate; buds ovoid-apiculate, villosulous and setulose, (exceptionally glabrous) disposed near level of expanded fls; bracts lance-subulate, purplish, turning dry and brown, (1.5-)2-3.5 mm, tardily deciduous; pedicels slender, becoming 2-45 cm, bracteolate 3.5-13 mm below calyx, in fruit either ascending or spreading at a wide angle from the axis; bracteoles like the bracts, scarcely shorter, persistent; sepals yellowish, 8.5-11 (-12) mm, the outer lance-acuminate or elliptic, the broader inner ones ovate acute, to 6 mm wide; petals yellow, up to 11.5-15 mm, 4 obovate-cuneate, the fifth falcately oblong; ovary densely setulose; ovules 3-6.

Pod oblong to oblong-elliptic in outline, 1.8-3.5 x 0.5-0.75 cm, straight or slightly decurved, the valves becoming stiffly chartaceous reddish-brown, densely viscid-villosulous and -setulose; seeds 3.8-4.6 x 2.6-3 mm, the testa atropurpureous lustrous, almost imperceptibly lineolate and transversely crackled.

This is a variable species, widespread across the Planalto from Sa. do Espinhaço in Minas to the Paraguay drainage in southern Mato Grosso. Features common to all forms of it are: a) over 10 but under 20 (-21) pairs of firmly membranous, subconcolorous leaflets about 1-2.5 cm long and three times longer than wide; b) short inflorescences, mostly less than 1 dm long, with pedicels 2-4 cm long; and relatively small flowers with sepals about 1 cm long. The conspicuously variable characters, disregarding the pubescence which, as in related species, consists of villi and small yellow-based setules mixed in variable proportions (sometimes absent), are the attitude of the stems, which may be diffuse or erect, the maximum size of leaflets, and in particular the elaboration of the inflorescences in relation to the foliage. At one extreme each individual raceme stands opposite a well-developed leaf longer than itself; and the lowest on a given stem, in reality terminal to that stem, appears leaf-opposed being surpassed by a strong axillary branchlet. At the other extreme all leaves subtending a raceme are transformed into bracts, giving rise to a compound panicle of variable complexity standing above the foliage. Few specimens show either of these extremes in full development, the majority being intermediate in style. Moreover each type of inflorescence is known to coincide with few and small, or with more numerous and larger leaflets, and with either diffuse or with erect stems. Several individual variants have been described as species, but in the light of modern collections their apparent distinctness has dwindled. The original C. neesiana from Bananal has erect stems, small shiny leaflets, up to 12-jugate and 1 cm long, combined with racemes about level with the topmost leaves. Several recent collections from Serra do Cipo resemble this, but some have up to 20 pairs of leaflets, some have diffusely ascending stems and some have racemes entirely immersed in foliage. The type series of C. laxiracemosa has similar leaflets combined with diffuse stems and a well exserted terminal raceme. The type of C. subnitida, from the unidentified locality Riacho das Vedras in Minas, has immersed racemes mostly leaf-opposed combined with larger leaflets, up to 14-jugate or almost 2 cm long. These larger leaflets, sometimes up to 15-16- jugate, apparently become more common westward in Goias and the Federal District, and are combined there with a more or less complexly paniculate inflorescence rising well or at least partially above the foliage. The cassia collected by Burchell (no. 7024) on Morro de Canta Gallo near the town of Goias which Bentham referred to C. isidorea, represents the extreme in this direction, with up to 15-17 pairs of leaflets up to 2.5 cm long coinciding with an extended leafless panicle. There remain a number of specimens quite intermediate between these points on the scale of variation which make a credible division of the material now available scarcely possible. However it seems desirable to give some taxonomic recognition to extremes of habit which we interpret provisionally as varieties of a polymorphic C. neesiana.

Key to varieties of C. neesiana

1. Lfts relatively small, those of the ampler lvs to 0.7-1.4 cm; at most 1-2 terminal racemes exserted from foliage, the inflorescence not assuming the form of a complex panicle; Minas Gerais w. to R. Paranaiba and Distrito Federal.

2. Stems ascending to erect, paniculately branching distally; racemes little or not exserted from foliage, often largely immersed.

58a. var. neesiana

2. Stems diffuse, humifuse with incurved tips, little or not branched distally; racemes mostly terminal to the primary stem-axis and exserted beyond the ± reduced upper lvs.

58b. var. laxiracemosa

1. Lfts larger, those of the ampler lvs to 1.5-2.6 cm; inflorescence various, the racemes either lf-opposed and immersed, or paniculate and exserted; s. Mato Grosso and Goias, e. to headwaters of R. Sao Francisco in Minas.

3. Inflorescence composed of,solitary racemes opposed to developed lvs; relatively eastern, intergradient to var. neesiana e.-ward and var. goyazensis w.-ward.

58c. var. subnitida

3. Inflorescence paniculate, the upper cauline lvs ± abruptly reduced in size, some to bracts, the whole elevated above the foliage; Goias and Mato Grosso.

58d. var. goyazensis