Dalea melantha S.Schauer var. melantha
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1977. Daleae Imagines, an illustrated revision of Errazurizia Philippi, Psorothamnus Rydberg, Marine Liebmann, and Dalea Lucanus emen. Barneby, including all species of Leguminosae tribe Amorpheae Borissova ever referred to Dalea. Mem. New York Bot. Gard. 27: 1-892.
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Family
Fabaceae
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Scientific Name
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Type
"In Mexici provincia Oaxacana. Aschb. n. 204." — Holotypus, presumably lost at B, but the protologue decisive. — Parosela melantha (Schauer) Rydb., N. Amer. Fl. 24: 108. 1920.
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Synonyms
Parosela melantha (S.Schauer) Rydb., Parosela fuscescens Rydb., Dalea fuscescens (Rydb.) Rzed., Dalea guadalcazarensis Rzed.
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Description
Species Description - Glabrous to the spikes (the young twigs exceptionally puberulent, but the leaflets glabrous); leaflets mostly small, up to 5 mm long, if obcordate at least 5 pairs in some primary leaves; spikes mostly compact, the flowers subcontiguous along the axis; pedicels mostly 0.2-0.5 mm long; 2n = 7 II, 14 (Mosquin). — Collections: 40 (vi).
Distribution and Ecology - Arid rocky or sandy-clay hillsides, becoming abundant on gullied badlands subject to active erosion, on a variety of soils, but from Hidalgo n.-ward notably calciphile, s.-ward on limestone, shaley clays, andesite, and pumice, 1380-2400 m (4600-8000 ft), widespread along the e. side of the Mexican Plateau from n.-centr. Oaxaca n. to centr. San Luis Potosi, there entering the range of the next but known from scattered stations as far n. as extreme s.-e. Coahuila and adjoining Nuevo Leon. — Flowering July to March, perhaps almost through the year.
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Discussion
(Plate CXVI)
The var. melantha is rather uniform in aspect but variable in detail and subject in some degree to seasonal dimorphism. Rydberg’s concept of P. melantha was formed from study of specimens collected in July and August, at a time when the marjoity of flowering spikes present on the plant are depauperate, subsessile, and terminal to short-shoots. The normal winter phase, with fewer and at least some pedunculate, many-flowered heads appears in North American Flora as P. fuscescens, the typus of which was collected in March. Macbride (1922, p. 20) early voiced the suspicion that these two Paroselae were one and the same, and there is now abundant evidence that such is the case. In the southern half of its range var. melantha varies little, but northward from northern Puebla individual plants (or colonies of the same) aberrant in one or more characters become increasingly frequent, some of them suggesting passage into the more northern var. berlandieri. Noteworthy minor variants are: calyx-teeth shorter than tube (Rzedowski 8818); calyx-tube glabrous externally (Purpus 4836); as the last, accompanied by ± 4 pairs of relatively ample, obcordate leaflets (Rzedowski 11,315). At Minas de San Rafael (mpo. Cd del Maiz, San Luis Potosi) Purpus collected in the same season (Nov, 1910) specimens typical of var. melantha (no. 4638, UC) and others typical of var. berlandieri (4841, F, UC); it is not known whether these are ecologically segregated where they occur together.
Typical D. melantha was collected first in late XVIII century by Sesse or his associates (Herb. S. & M. 2668, F, MA), and therefore could well have reached the Lambert Herbarium by way of Pavon. It has not, however, been identified with any of George Don’s still ambiguous propositions derived from these sources.
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Objects
Representative: Coahuila. Arteaga: typus of P. fuscescens. Nuevo Leon. Galeana: C. & H. Mueller 323 (F, NY, US). San Luis Potosi. Catorce: Rzedowski 8166 (ENCB). Charcas: Rzedowski 8818 (ENCB). Ciudad del Maiz: Purpus 5192 (F, UC, US). Guadalcazar: Ripley & Barneby 13,777 (NY); typus of D. guadalcazarensis. Cerro de San Pedro: Rzedowski 7856 (ENCB). Santa Catarina: Rzedowski 3593 (ENCB). San Nicolas Tolentino: Rzedowski 11,315 (ENCB). Queretaro. Toliman: Rzedowski26959 (ENCB). Hidalgo. Zimapan: Gonzalez-Quintero 3297 (ENCB). Cardonal: Gonzalez-Quintero 2078 (ENCB). Ixmiquilpan: Purpus 1376 (F, NY, UC). Puebla. Tepeyahualco: Prince Paul of Wiirtemburg in 1830 (M). Aljojuca: Ripley & Bameby 14,745 (MEXU, NY, US). Esperanza: Balls 5416. Santiago Miahuatlan: Ripley & Barneby 14,737 (CAS, NY). Tehuacan: Purpus 5653 (UC). Coxcatlan: Purpus 4148 (UC). Zapotitlan: Ripley & Barneby 14,710 (DAO, NY, US). Oaxaca. Nochixtlan: Ripley & Barneby 13,668 (CAS, MEXU, NY, US), 14,585 (CAS, NY).
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Distribution
Coahuila Mexico North America| Nuevo León Mexico North America| San Luis Potosí Mexico North America| Santa Catarina Brazil South America| Querétaro Mexico North America| Hidalgo Mexico North America| Puebla Mexico North America| Oaxaca Mexico North America| Mexico North America|