Changes in reciprocal herkogamy during the tristyly-distyly transition in Oxalis alpina increase efficiency in pollen transfer.

Although the spatial separation of sexual organs within a flower (herkogamy) has been interpreted as a mechanism that promotes efficient pollen transfer, there have been few attempts to relate variation in herkogamy to probabilities of pollen flow. Here, we used a heterostylous species with variation in reciprocal herkogamy to test this hypothesis. We measured legitimate and illegitimate pollen flow with fluorescent dyes in four selected populations of Oxalis alpina corresponding to the extremes of a previously reported evolutionary gradient from tristyly to distyly. After the breakdown of tristyly, the observed increment in reciprocal herkogamy between the long and short morphs was associated with a 30% increase in the proportion of dye received from compatible illegitimate pollinations. In all populations, the most likely effective pollen vectors were two Heterosarus bee species. Our results support the adaptive value of reciprocal herkogamy in promoting efficient pollen transfer in heterostylous species.

[Multiple recurrent cardiac myxomas].

A 49-year-old male had undergone resection of biatrial multiple myxomas 4 years previously in another hospital. Echocardiography revealed new masses in the left atrium and the right ventricle. Both tumors were removed surgically and subsequently treated with adjuvant chemotherapy. There was no further recurrence during the following 4 years. It was considered that the multiple recurrences in our case were due to multicentricity of the tumor.

Is breaking up hard to do? Breakage, growth, and survival in the parasitic clonal plant Cuscuta corymbosa (Convolvulaceae).

In a tripartite exploration of the effects of traumatic breakage in the parasitic clonal plant Cuscuta corymbosa, experimental breakage had significant negative effects upon stem extension of ramets distal to a break and the level of that effect depended upon the number of ramets in the severed fragment. Regular monitoring of clonal individuals transplanted onto naturally occurring, native host species revealed that breakage in individuals growing under natural conditions ranged from 2 to 66% of all interramet connections and significantly affected distance between ramets and stolon generation in ramets associated with a break. Simulations revealed that these responses to breakage would significantly change the "shape" of a clonal individual in a manner capable of affecting probabilities of encounter with patchily distributed resources. Nonetheless, the observed levels of breakage had no discernible effect on biomass accumulation, although individuals that survived into the dry season and thus gained the potential to reproduce in additional seasons had a significantly lower rate of breakage than those that did not. We suggest that the lack of a relationship between breakage and within-season biomass accumulation is an indication that parasite response to breakage is gauged to expected levels of breakage for the habitat. We note that the capacity of ramets to survive disconnection significantly decreased the loss of tissue that would occur if subunits did not possess the potential to function independently.

[A case of pericardial diverticulum with changing size].

A 39 year-old woman with a tumor shadow in the right upper mediastinum noticed by chest x-ray examination of mass survey was presented. Chest x-ray films taken 5 times in a month in a same position showed the mass further changed in size. This result indicates the communication between the mass and pericardial cavity. Surgical extirpation was carried out and diagnosed a pericardial diverticulum.