Monographs Details: Gongylolepis
Authority: Carlquist, Sherwin. 1957. Anatomy of Guayana Mutisieae. Mem. New York Bot. Gard. 9 (3): 441-476.
Family:Asteraceae
Scientific Name:Gongylolepis
Discussion:

The genus Gongylolepis is interesting to compare with Neblinaea in that although the flowers of most species are much larger than those of Neblinaea, their flowers do not have more complex venation; in fact, their pattern is often simpler than that just described. In Gongylolepis bracteata (fig. Ill) the condition might be interpreted as basic for the genus, though it is not the most typical. In the corollas (fig. 111A) of this species lateral veins are present, fusing at the lobe-tips both in the two separate lobes and the three united lobes. The latter portion of the corolla exhibits a very interesting condition (mentioned also in Neblinaea) in that although the laterals unite beneath the very short sinuses of this structure, freely terminating "lateral" bundles are also present further down, branching from the two central veins at the same level as the division of laterals below sinuses beside the two separate lobes. It is possible, therefore, to interpret this condition as a reflection of the vascular system of the actinomorphic corolla which is generally assumed to be ancestral to the zygomorphic condition. Further emphasizing a possibly primitive configuration, median bundles are often present for varying distances in the lobes of this species. In the tubular portion of the corolla, only five bundles, together with their associated stamen traces, are present. Stamen bundles unite with these corolla bundles in the achene top. In addition to the corolline bundles, five more exterior bundles are found in the achene wall (fig. I l l C, F). The style of Gongylolepis bracteata (fig. I l l B) has four bundles at the base (fig. I l l D). In its upper portions, however, the bundles branch and anastamose, forming a more complex appearance; these groups of bundles are arranged on adaxial and abaxial sides of the style, and pass into the stigmatic branches. In the achene (fig. I l l C), the dorsiventral style bundles unite with exterior achene wall bundles on opposite sides of the achene. The lateral style bundles continue down the achene as interior bundles (see also fig. I l l F). Near the base of the achene these bundles unite with the ovule trace (fig. I l l G) to form a cylindrical plexus. Further down, this joins with the exterior bundles to form a single strand which connects with the receptacle. The ovule trace was found to be dual along most of its length.

The drawing of Gongylolepis pedunculata (fig. 112) shows the only species of this genus studied in which a more complex corolla venation was found. In certain features it is like the condition in G. bracteata. A median vein, for example, is present for most of the length of the strap-like portion of the corolla.

As in G. bracteata, two prominent veins from "laterals" beside the central two veins which run the length of this structure. These branch at the same level as the veins subtending sinuses beside the separate lobes. In addition, other veins branch off from the five main corolla-tube veins at this level. The shorter, freely terminating branches, unlike those of Stenopadus kunhardtii or Stomatochaeta crassifolia, are located inside, rather than outside, the true laterals. The style of G. pedunculata (fig. 112B) is simpler than that of G. bracteata in that only four bundles, all of which terminate freely, are found. The achene venation is like that of G. bracteata. The greater complexity of the corolla venation in G. bracteata may be correlated with the fact that this species has the largest flowers of the species of Gongylolepis studied.

The smallest-flowered species, G. fruticosa, (fig. 113), has been included for comparison. In the corolla of this species (fig. 113 A), the venation has reached the ultimate simplicity found in most zygomorphic corollas of Mutisieae. The laterals fuse directly beneath the sinuses, and no corolla veins are found in addition to the fused laterals. In the achene (fig. 113 C) the five corolline bundles are augmented, as in G. bracteata, by five more bundles, which terminate in the top of the achene. In the style of the flower of G. fruticosa studied (fig. 113 B), four bundles were present, though only three of these extended to the style base. In the achene (fig. 113 C), these were found to join achene wall bundles at a high level of the achene. Thus only exterior bundles were present in most of the length of the achene. A simple ovule trace is present; all the bundles of the achene unite at the achene base into a single strand of vascular tissue.

Despite the fact that their corollas are larger than those of G. fruticosa, the same corolla venation was seen in G. huacbamacari, G. martianus, and G. paruana. The styles were all found to have four bundles; a pair of lateral interior bundles were usually not observed in achenes of these species, all the stylar bundles uniting with achene wall bundles at the summit of the achene. The ovule trace was often seen to be dual, at least in its upper portion.