Monographs Details: Mimosa callidryas Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1991. Sensitivae Censitae. A description of the genus Mimosa Linnaeus (Mimosaceae) in the New World. Mem. New York Bot. Gard. 65: 1-835.
Family:Mimosaceae
Synonyms:Mimosa myriophylla Bong. ex Benth.
Description:Species Description - Amply microphyllidious unarmed, virgately erect subshrubs at least 1 m tall, resembling closely related M. myriophylla in habit, the striate reddish stem, lf-stks and axis of far-exserted efoliate, paniculately branched inflorescence at once finely gray-puberulent, livid-granular, and hispid with spreading-ascending, basally dilated and microscopically scaberulous setae to 1-3 mm, the dull olivaceous concolorous lfts puberulent beneath, glabrous above, not setose-ciliate, the inflorescence of small, plumply ellipsoid, short-pedunculate capitula rising 4-6 dm above furthest cauline lf. Stipules firm, narrowly lance-attenuate 4-8 x 0.5-0.9 mm, puberulent and hispidulous dorsally, persistent. Leaf-stalks (4.5—)5.5—11 cm, the petiole including hard obese pulvinus 2-3.5 cm, near middle 0.5-0.7 mm diam., the interpinnal segments 4-10 mm, the ventral groove very narrow, interpinnal spicules 0; pinnae 7-10-jug., a little decrescent proximally, the rachis of longer pairs 20-38 mm, the interfoliolar segments 0.6-0.9 mm; lfts of longer pinnae 30-38-jug., subequilong except at extreme ends of rachis, the small first pair 0.1-0.3 mm distant from subulate paraphyllidia 0.2-0.5 mm, the blades narrowly oblong obtuse or minutely mucronulate, at base shallowly semicordate, those near mid-rachis 3-4.5 x 0.85 x 1.2 mm, 3-4 times as long as wide, all veinless above, beneath faintly 2-nerved, the midrib slightly excentric, the posterior nerve short and weak. Primary axis of inflorescence 3-6.5 dm, that of 2-4 lateral branches 1-3.5 dm, these strictly ascending, the peduncles 1.5-6 mm, geminate at almost all nodes; capitula without filaments 4-5.5 mm diam., prior to anthesis moriform, the fl-buds obovoid, densely gray-puberulent; bracts narrowly spatulate 1.1-1.4 x 0.4 mm, finely puberulent dorsally; flowers 4-merous 4-androus, mostly bisexual; calyx tube 0.1-0.2 mm, the orifice fringed with weak setulae to 0.2-0.6 mm; corollas narrowly turbinate 2-2.1 mm, the ovate-triangular almost plane lobes puberulent but only thinly so proximally; filaments dark red, free almost to base, exserted 2.5-3 mm; anthers 0.85-0.9 mm diam.; ovary densely white-pilosulous; style glabrous 0.7-1.7 mm long, at apex 0.1 mm diam., either included or shortly exserted from corolla but very much shorter than the filaments; ovule one. Pod in early stages of maturity compressed-obovate, densely white-setulose, not seen fully formed.

Distribution and Ecology - In campo at woodland margins near 790 m, known only from the type-locality either in e. Paraná or possibly far s. S. Paulo.—Fl. II—III.

Discussion:

Part of the type-collection of M. callidryas was identified by Harms as M. myriophylla, the species to which it is indeed closely related, being similar in growth-habit and sharing with it these unusual floral characters: dark red filaments bearing exceptionally large anthers; a short thick style much surpassed by the filaments; and a solitary ovule. Differences that I consider of specific consequence are the greatly diminished (not large paleaceous-pappiform) calyx, fewer leaflets per pinna, and spreading hispid indumentum not yet encountered in M. myriophylla. While the style of these two species is shorter than in any other mimosa of southeastern Brazil, that of M. callidryas is ordinarily shortly exserted from the corolla at anthesis, whereas that of M. myriophylla is fully included in it.

The epithet callidryas is derived from the name of the type-locality, Capão Bonito. According to Dusén’s labels this place is in Paraná, but the Capão Bonito near 24°S in southern São Paulo is a possible alternative.

Distribution:Brazil South America| São Paulo Brazil South America| Paraná Brazil South America|