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(Last Modified On 10/31/2013)
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Species
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Rondeletia brandegeeana Lorence
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Synonym
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Otocalyx chiapensis Bran- degee, Univ. Calif. Publ. Bot. 6: 68. 1914. Non Rondeletia chiapasensis Standl. (1940). TYPE: Mexico. Chiapas: Cerro del Boqueron, middle region, moist valley slopes, Aug. 1913, C. A. Purpus 7041 (holotype, UC no. 173047, photo PTBG; isotype, GH).
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Description
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Tree? or shrub?, the young twigs strigillose, the trichomes simple, unicellular, whitish or pale fulvous, 0.3-0.6 mm long, the twigs 1-2 mm diam., the internodes (0.5-)1-9 cm long. Leaves opposite, those
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Habit
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Tree? or shrub?
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Description
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of a pair at a node equal or subequal, petiolate; petioles 4-12 mm long, 0.5-0.6 mm diam., mod- erately to densely strigillose; lamina ovate or ovate- elliptic, 2.5-7 x 1.3-3.5 cm, drying brownish green, discolorous, both surfaces sparsely strigillose, the hairs denser along costa and veins, the base cuneate to rounded, occasionally attenuate, the apex long- acuminate, the acumen 1-1.5 cm long, often fal- cate, the 2? veins 4-6 pairs, the venation camp- todromous, the venation visible to 5? on both sur- faces, the margin sparsely ciliolate; stipules erect, deltoid, 1-1.5 mm long and wide basally, externally strigillose dorsally, internally densely strigillose-se- riceous, margins scarious, the trichomes mixed with brown digitate colleters 0.5 mm long. Inflorescence terminal, dichasial-cymose, 4-5 cm long including the corollas, 2-3 cm wide, trichotomous (sessile) or with a single 1? axis (peduncle), the central 1? axis 1-3 cm long, often subtended by a pair of reduced leaves, bearing a cymule of 3-8 flowers, the 2 lateral 1? axes 1-2.5 cm long, each bearing a cymule of 1-3 flowers, the axes densely fulvous strigillose, the cymules subtended by linear bracteoles 2.5-3.5 mm long; flowers 4-merous, sessile or on pedicels to 1 mm long, each usually subtended by a linear stri- gillose bracteole 2-3 mm long, the hypanthium ob- conical-obovoid, 2 x 1.5 mm, densely fulvous stri- gillose, the calyx cup 0.3-0.5 mm deep, the lobes strigillose, unequal, 3 smaller lobes linear-subulate, erect, 2-5 x 0.5 mm, 1 larger lobe foliaceous, lanceolate or ligulate, 9-10 x 1.5-2 mm, each sinus with a single brown, digitate colleter; corolla with imbricate aestivation in bud, salverform at an- thesis, the tube 10-11 mm long, 1 mm diam. me- dially, externally densely fulvous strigillose, inter- nally pilose in basal 1/3, the lobes spreading, ovate or rounded, 3 x 2.5-3 mm, externally strigillose, internally sparsely papillose puberulent around throat with short, white, flat and bulbous trichomes; sta- mens in short-styled flowers sessile, attached 1.5 mm below throat, anthers linear-ellipsoid, 2-2.2 mm long, tips slightly exserted; style in short-styled flow- ers included, glabrous, 4 mm long, the ellipsoid stigmas 3 mm long; disc pilose, 0.5 mm diam., sunken below calyx lobe sinuses. Pollen 3-colporate. Capsule ovoid-ellipsoid or subglobose-ellipsoid, shghtly bisulcate, 5 mm long, 4-5 mm diam., strigillose, crowned by persistent calyx lobes, dehiscence lo- culicidal then septicidal; seeds angulate, 0.3-0.4 mm diam., the testa dark brown, deeply foveolate, the cells 5-6-sided.
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Note
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This species is known only from the type locality on the Cerro del Boquer6n in Chiapas, Mexico, where C. A. Purpus collected it in "rocky 139 forests." No recent collections are known, suggest- ing that it may be extremely rare or extinct.
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Specimen
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MEXICO. CHIAPAS: Cerro del Boquer6n, 1914, C. A. Purpus 7041' (UC, probable isotype); Cerro del Boquer6n, rocky forests, June [year not given], C. A. Purpus 7514 (UC).
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Note
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A careful study of the holotype and two other collections of Otocalyx chiapensis revealed that this species agrees well with Rondeletia sensu lato in terms of vegetative, floral, and fruit morphology. The name Otocalyx refers to one of the four calyx lobes that is expanded and foliaceous. However, this feature is not inconsistent with Rondeletia, many species of which have one or two large, foliaceous calyx lobes. The throat and adjacent adaxial corolla lobe surfaces are sparsely bearded with short, white, bulbous and flattened hairs, a feature characteristic of Rogiera and Javorkaea. The tetramerous flowers and internally basally pilose corolla tube are features typical of Arachnothryx, although the pilose nectary disc is not supposed to occur in the latter genus according to Steyermark (1967). Brandegee's (1914) statement in the protologue that Otocalyx is char- acterized by baccate fruits and a unilocular ovary with numerous ovules on a dorsifixed, laminar pla- centa, features that are ". . . peculiar for a Rubia- ceous genus, resembling those of some species of Gesneriaceae," is clearly erroneous. In his Rubi- aceae treatment for North American Flora, Stan- dley (1934: 181-182) placed Otocalyx in the Gar- denieae tribe because of its supposedly fleshy fruit, a feature he questioned, although he did recognize the bilocular nature of the ovary. My examination of the fruits of Otocalyx chia- pensis revealed that they are clearly capsular and bilocular, each locule having an elongate, peltate placenta with numerous seeds. Dehiscence appears to be at first loculicidal (as in Rondeletia), then septicidal (as in Arachnothryx). The numerous seeds are nonwinged and angulate with a deeply foveolate testa consisting of 5-6-sided cells, a feature char- acteristic of Arachnothryx. For these reasons I have decided to transfer Otocalyx chiapensis to the ge- nus Rondeletia as R. brandegeeana and have pro- vided an emended description of the species. This species combines key characters of Rondeletia, Ro- giera, and Arachnothryx, thus undermining the validity of the latter two genera. Rondeletia bran- degeeana seems most closely related to R. atra- vesadensis and R. rzedowskii, both referable to Standley's Calycosae group.
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