The most important phloroglucinol derivatives ("filicins") isolated from rhizomes of Dryopteris species are discussed. The chemical analysis of Dryopteris rhizomes can (in conjunction with classical and cytological methods) provide valuable criteria for the solution of taxonomical problems, particularly as follows: 1. Identification of otherwise uncertain herbarium specimens. 2. Classification of critical taxa in a difficult complex. 3. Understanding of natural relations, including parents in hybrids and ancestors in allopolypoid species. Analytical methods are critically evaluated.
The colchicine content in Colchicum autumnale L. of North Italy.
The colchicine content of different parts (bulb, flower, leaves, seeds, capsules) of C. autumnale L. has been identified. The specimens were collected in North Italy, in stations with different altitudinal, climatic and vegetational conditions.
Colchicine is present in all the studied parts, with a concentration gradient going from a maximum in the seeds to a minimum in the bulbs.
The colchicine content in the bulbs varies according to the principal phases of the life-cycle (flowering, fruiting, hudding), whereas in the seeds it depends from the degree of ripeness, being higher
in the first stages.
On the basis of results, it is suggested to take into consideration also leaves and flowers for the extraction of the alkaloid.
THE ALGAL MICROFLORA ON CALCAREOUS WALLS OF FRIULI - VENEZIA GIULIA (NE - ITALY). The algal biotopes are mostly populated by Cyanophytes. The most abundant Algae are Gloeocapsa and Scytonema. Microphytic communities are described phytosociologically. The algal vegetation is similar to Scytonemo - Gloeocapsetum described by Golubić (1967). The lithophytic vegetation of three localities of different microecology is compared. Some difference with regard to the relative abundance of coccoid and filamentous species is detected.
DISTRIBUTION AND BIOLOGY OF THE LICHEN CALOPLACA ANULARIS. Caloplaca anularis, described from the Western Alps in 1972, is reported for the first time from the Eastern Alps and the Balkan peninsula. The species grows always on steep calcareous rocks. There garlandlike, centrifugal, rarely fruiting thalli are built. On small projections of the rocks it grows rosulate and many apothecia are developed. The form of growing is connected with a deposit of excrets in the medulla and the hypothallus increasing towards the older parts of the thallus. The excrets deposited in the medulla and the hypothallus differ with the optical activity.