Monographs Details: Achlyphila
Authority: Carlquist, Sherwin. 1960. Anatomy of Guayana Xyridaceae: Abutboda, Orectanthe and Achtyplola. Mem. New York Bot. Gard. 10: 63-117.
Family:Xyridaceae
Scientific Name:Achlyphila
Discussion:

The three sepals of Achlyphila distich a (fig. 65) are rounded rather than keeled. They contain about five bundles, which are embedded in the thin-walled parenchyma, composed of cells polygonal in outline, in the central portion of the sepal. This parenchyma contains chloroplasts in moderate numbers. The inner and outer faces of the sepal are sclerenehyma. At lower levels, this selerenchyma takes the form of lignified parenchyma which intergrades with the thin-walled parenchyma in the center of the bract, but at higher levels, such as that shown, the selerenchyma is thick-walled and clearly definable from the chlorenchyma.

Discussion.

The sepals of Orectanthe are different from those of Abolboda in that (1) they are much larger; (2) they consist wholly of lignified parenchyma cells except for pockets of chlorenchyma in the keel and between some of the veins; and (3) they contain a much greater number of veins, and veins have a scattered distribution in the keel region. Selerenchyma is present around veins in Orectanthe sepals regardless of location of veins. Sepals of Achlyphila are very simple in structure, corresponding with other seemingly unspecialized features of this genus. The presence of both an adaxial and an abaxial band of selerenchyma, together with the lack of a keel, is notable. The species of Abolboda seem to agree in their tendency toward production of an adaxial selerenchyma band, and in the relative paucity of sclerenehyma in the abaxial portion of the sepal. Only a single series of bundles is present (unlike the condition in Orectanthe). The patterns of distribution of selerenchyma, thinwalled parenchyma, and chlorenchyma undoubtedly lend themselves to use as specific criteria, and are self-evident, in the varied patterns illustrated, in sepals of Abolboda. Because of variation in such patterns between the base and apex of a sepal, however, such patterns should be applied with caution. Unfortunately, no liquid-preserved sepals of Xyris were available for study. The writer suspects that these would show much resemblance to sepals of Abolboda. and would be worth investigating in any case.

FLORAL VENATION

The flowers of Abolboda and Orecttmthe are alike in a number of features. The flowers of Orectanthe differ in having non-keeled sepals, in lacking staminodia, and in having larger parts which are more richly vascularized at least in some instances (corolla lobes, sepals) than the corresponding portions of Abolboda flowers. The general venation pattern in the two genera is sufficiently similar so that variations are considered below after a description of a typical venation pattern in Abolboda.