SPECIATION AND NOMENCLATURE IN THE GENUS CELOSIA

Abstract

Guard cell measurements indicative of stomatal size were made on a number of herbarium specimens of cockscomb (C. cristata L., C. argentea var. cristata (L.) Ktze., et alii) and quail grass (C. argentea L.) in order to clarify further their taxonomic relationships. Cockscomb is considered by some authors to be synonymous with C. argentea L.; however, guard cell measurements averaged 9.59 and 11.70 units respectively, furnishing evidence for the distinctness of these two taxa. Consequently, cockscomb has been reinstated as C. CRISTATA L. In addition, five specimens were observed which possessed morphological characteristics of both C. cristata and C. argentea but were separable from both of these taxa by their guard cell measurements, which averaged 16.10 units. These plants collected in the Philippines and Central America are considered to have originated through hemialloploidy since the range of their guard cell measurements overlapped those of a known panalloploid between these species, namely, C. whiteii Grant. The geographic distribution of these plants indicates that hemialloploidy has occurred with a high frequency in the genus. A spontaneous fasciated plant has also been described which arose from seed of C. whiteii. Normal bivalent pairing of the chromosomes was observed in meiosis (n = 54) and progeny from this plant for three generations have all been fasciated.