provided by Smithsonian Contributions to Botany
Chusquea caamanoi Sodiro (1881:11). Nomen nudum
Colanthelia McClure and E. W. Smith, new genus
Plantae unicespitosae, inermes. Rhizomata pachy-morpha. Culmi habitu staturaque late diversi, aut parum alti et erecti vel “decumbentes” (teste Hackelii sub Arundinaria rhizantha) aut “altissimi scandentes” (teste Trinii sub Arundinaria distans), nodis valde elevatis et anguste cristatis, nodo medio unoquoque juventute gemmam solitariam gerenti, prophyllo gemmae et gemma ipsa in germinatione simul elongatis. Ramorum complementum ad nodos culmorum medianos axem ordinis primarii solitarium continens, idem basi vulgo mox proliferatum, ramis ordinis superioris axem primarium plus minusve valde superantibus. Vaginae internodia eulmorum foventes basi cingulis latis post delapsum vaginarum persistentibus praeditae. Foliorum laminae venulae transversae extra vulga haud manifestae.
Inflorescentiae semelauctantes, in speciebus plerisque vel infirme paniculatae vel racemosae, formis intermediis variis in ipsa planta interdum praesentibus; prophylla omnino haud ulla, bracteis dempta infima vel parvis vel obsoletis.
Glumae transitionales vulgo 2, rarissime vel 1 vel 3. Spiculae raro pauciflorae (ut in Colanthelia lanciflora) pleraeque pluriflorae, angustissimae et fragilissimae, apice in anthecio sterili plus minusve valde depauperato terminantes. Lemma fertile in maturitate paleam suam basi tantum circumplectans. Palea dorso 2–carinata et late sulcata, marginibus vix vel haud imbricatis. Rachillae segmenta ob fragilitas articulorum (nodorum) suorum in maturitate facilissime disarticulantia. Lodiculae typice 3, duae anticae plus minusve asymmetricae atque geminatae, postica symmetrica et vulgo minore. Stamina 3, filamentis filiformibus liberisque. Stigmata 2. Fructus non adhuc suppetens.
Plants unicespitose, unarmed. Rhizomes pachymorph. Culms of small to medium stature and erect or decumbent, to very tall and scandent, the nodes prominent with a narrow crest, each midculm node giving rise to but a single initial bud; the prophyllum of the bud growing while the bud germinates, the primordium producing a single (segmented, terete) primary axis, this dominant over the axes of secondary order usually proliferating promptly from buds typically present at its own proximal nodes. Sheath at midculm nodes provided with (and abscissing from) a conspicuous persistent girdle (basal expansion zone). Leaf blades with transverse veinlets as a rule not manifest externally.
Inflorescences semelauctant, either paniculate or racemose (sometimes showing in the same specimen forms intermediate or intermixed between these two forms), part or all of the inflorescences (or even whole flowering branches) in a given specimen sometimes reduced individually to barely more than a solitary spikelet. Transitional glumes typically 2, rarely 1 or 3. Spikelets usually pedicellate, typically many-flowered (few-flowered in Colanthelia lanciflora), very narrow and fragile, terminating apically in a more or less strongly depauperate sterile anthecium. Fertile lemma fully embracing its palea only basally at maturity. Palea 2–keeled and broadly sulcate dorsally, gaping ventrally. Rachilla segments (owing to their fragility at the nodes) easily disarticulating at maturity. Lodicules typically 3, the anterior 2 more or less asymmetrical and paired, the posterior one symmetrical and usually smaller. Stamens 3, the filaments filiform and free. Stigmas 2. Fruit not yet available.
ETYMOLOGY.—The name Colanthelia (f.) is coined from the Greek kolos, shortened, and anthele, “plume or panicle of a reed” (R. W. Brown, 1954). It alludes to a tendency common to all of the currently recognized species of the genus. There is a noticeably to strongly manifested tendency toward a progressive reduction of the reproductive structures from weak panicles to simple racemes and, in some cases, even from whole flowering branches all the way to little more than solitary spikelets.
TYPE-SPECIES.—Colanthelia cingulata (McClure and L. B. Smith) McClure.
RELATIONSHIPS.—Affinity toward Aulonemia is weakly suggested by the nature of the midculm branch complement; this possible affinity is reinforced by the occurrence of paniculate inflorescences in some species. Among available examples, a specimen of Aulonemia haenkei (US 1256334) from Peru shows an occasional flowering branch reduced to little more than a solitary spikelet. The feature to which the name Colanthelia alludes also comes to light here and there in members of other genera. Among bamboos of the Old World genera a few similarly reduced flowering branches sometimes appear in specimens of Chimonobambusa marmorea. Other attributes (e.g., racemose inflorescences) suggest affinity toward Arthrostylidium. Such divergent attributes are connected by intermediate expressions to form clines, both from one species to another and (in some cases) within the same specimen. In the available material representing the genus Colanthelia, the morphological gamut of the reproductive apparatus reaches from leafy to leafless branches, each terminating in either a panicle, a raceme, a combination between those two forms, or a single spikelet. Pertinence to the genus Colanthelia (among the known bamboo genera of the New World) is made plain in its known members (even in their vegetative state) by the overall delicacy of the plant, with distinctively small leaf blades, combined with pachymorph rhizomes, prominent narrow-crested midculm nodes, a wide girdle at the base of the sheath at each node, and the unarmed complements with the primary element clearly dominant. With the exception of Colanthelia lanciflora, all known members of the genus have more or less distinctively long and narrow spikelets with more or less clearly exposed slender, elongate segments.
DISTRIBUTION.—As far as their natural distribution is a matter of record, all of the known species of Colanthelia are confined to Brazil. Three species have been reported from Santa Catarina, and one each from Minas Gerais, Paraná, Rio Grande do Sul, and São Paulo. The recorded altitudinal range extends from 30 m for Colanthelia cingulata, to 550 m for C. intermedia, to 710 m for C. gracillima, and to 1600 m for C. lanciflora.
Annotated Checklist of Recognized Species of the Genus Colanthelia
1. Colanthelia burchellii (Munro) McClure, new combination.
Arthrostylidium burchellii Munro, 1868:43.
Arundinaria burchellii (Munro) Hackel, 1903a:69.
2. Colanthelia cingulata (McClure and L. B. Smith) McClure, new combination (Figure 32).
Aulonemia cingulata McClure and L. B. Smith, in Reitz, ed., 1967:50.
3. Colanthelia distans (Trinius) McClure, new combination.
Arundinaria distans Trinius, 1835:621.
Trinius (1836, III:622) states, incorrectly, that a terminal rudiment is lacking in Arundinaria distans Trinius, q.v.
4. Colanthelia intermedia (McClure and L. B. Smith) McClure, new combination.
Aulonemia intermedia McClure and L. B. Smith, in Reitz, ed., 1967:52.
5. Colanthelia lanciflora (McClure and L. B. Smith) McClure, new combination.
Aulonemia lanciflora McClure and L. B. Smith, in Reitz, ed., 1967:47.
6. Colanthelia macrostachya (Nees) McClure, new combination. Arundinaria macrostachya Nees, 1834:481.
7. Colanthelia rhizantha (Hackel) McClure, new combination. Arundinaria rhizantha Hackel, 1909a:323.
Elytrostachys McClure, 1942:173, figs. 4–6; 1957:202.
Plants unicespitose; unarmed. Rhizomes pachymorph. Culms self-supporting below, typically weak and pendulous or clambering above; the internodes cylindrical, hollow. Branch buds at culm nodes solitary, each containing but a single initial primordium. Branch complements at midculm nodes of either restricted or gremial insertion, unrestricted monoclade, consisting typically of one strong, central axis and a tuft of more slender ones arising from lateral buds at proximal nodes of the initial primordium, these latter buds sometimes germinating precociously while the apical growth of the initial primordium remains inhibited. Leaves (leaf sheath blades) typically with transverse vein-lets not at all or only weakly manifest externally; oral setae few, rigid, erect or spreading, slender except at the bulbous base, scabrous.
Inflorescences iterauctant, terminating leafy or leafless axes, of diffuse form, each axis the bracteate and prophyllate rachis of a pseudospikelet, the terminal segment of each rachis serving as the pedicel of a spikelet. Transitional glumes at the base of each spikelet none. [The conventional position of the transitional glumes is here (and in Atractantha, q. v.) occupied by what I now classify as bracts. When, in 1942, I first described and illustrated the genus Elytrostachys, I identified and labeled these structures as being glumes. However, in the perspective achieved more recently through a restudy of the structures in this transitional zone in the inflorescence of species of Elytrostachys in comparison with their counterparts in species of Atractantha, I now see them in both genera as empty bracts that are terminal to the series of bracts that subtend buds, rather than as empty glumes that precede the lemmas. The elongated terminal segment of the rachis that follows the two short internodes on which the emtpy bracts are inserted serves as the pedicel of the spikelet that is terminal to it. Having noted this, we can confirm the lack of empty glumes by recalling that the natural loci of their insertion would be found immediately preceding, and close to, that of the first lemma.] Spikelets each made pedicellate by the segment of the rachis it terminates, and each typically containing but a single perfect flower (sometimes 2 in E. clavigera), promptly disarticulating at maturity immediately below the locus of insertion of a fertile lemma, the rachilla prolonged behind the terminal perfect palea in a bristle-like segment bearing a minute rudiment of a sterile anthecium. [When the spikelet contains but a single perfect floret, the prolongation of the rachilla is bristle-like and bears a minute rudiment; but when the spikelet contains more than one perfect floret, the prolongation of the rachilla behind the palea of the terminal perfect floret may be more robust than bristle-like, and then will bear a sterile anthecium more substantial than rudimentary.] Lemma in functional florets fully embracing its palea only basally at maturity. Palea gaping antically, dorsally canaliculate in spikelets containing but a single perfect floret, broadly sulcate in the lower floret when the spikelet contains two perfect florets. Lodicules 3, subequal or unequal, the anterior 2 asymmetrical and paired, the posterior one symmetrical and smaller. Stamens 6, the filaments filiform, free. Stigmatic branches 2. Fruit a fusiform or lagenoid, rostrate, sulcate caryopsis, the pericarp coriaceous, of even thickness below, thickened at the apex, the basal position of the embryo clearly manifest.
ETYMOLOGY.—The name Elytrostachys, formed from the Greek elytro (combining form of elytron) sheath, cover (elytra = wing-cover of beetles) and stachys, spike, alludes to a fancied resemblance of the lemmas to the wing-cover of a beetle.
TYPE-SPECIES.—Elytrostachys typica McClure.
RELATIONSHIPS.—The only known New World genus to which Elytrostachys appears to be closely related is Atractantha. These two genera share the following features: inflorescences of a peculiar form characterized by rachises with long terminal segments, each of which serves as the pedicel of an abscissile spikelet; the absence of the transitional glumes commonly found at the base of each spikelet, and the presence, in their stead, of a bract inserted on each of the two short internodes that precede the elongated terminal segment of each rachis; each spikelet typically containing but a single perfect floret followed by a rudiment of a sterile anthecium borne on the tip of a bristle-like prolongation of the rachilla. From known members of Atractantha, known members of Elytrostachys differ in the following features: midculm
branch complements of restricted or gremial insertion, each arising from a solitary branch bud containing but a single initial primordium; auricles and oral setae of leaf sheaths not only much more conspicuously developed, but of different morphological configuration; in the presence of at least two empty bracts preceding the elongated terminal segment of each rachis; in the loosely convolute, more or less inflated form of the anthecia; and in the presence of twice as many stamens in each flower. As far as known to date, the respective geographical ranges of the two genera are widely disjunct.
DISTRIBUTION.—Of the two recognized species, E. typica has been reported only from the borders of a forest at the type-locality, El Limón, Venezuela. Elytrostachys clavigera McClure has been collected in Colombia and all countries northward to Honduras, and from situations at reported elevations from 200 to 1500 m, described as river banks, old river terraces, wet ravines, crest of range, edge of forest, opening in forest. Both species are represented as flowering and fruiting freely.
- bibliographic citation
- McClure, F. A. 1973. "Genera of Bamboos Native to the New World (Gramineae: Bambusoideae)." Smithsonian Contributions to Botany. 1-148. https://doi.org/10.5479/si.0081024X.9