摘要:

The vegetation of the Palmaria and Tino Islands (Gulf of La Spezia). — The vegetation of the Palmaria and Tino islands in the Gulf of La Spezia shows various aspects although they are completely calcareous and do not exceed two hundred meters in height. Along the coast, we have noticed some small beaches with a few psammophytes, and some cliffs vertically overlooking the sea with the endemicCentaurea cinerariavar.venerisand with a few shrubs (among which I would like to mentionPinus halepensis) that become bigger and bigger and grow in number with the altitude. On the southern side of Palmaria the Mediterranean « maquis » withCalicotome spinosa, Cistus monspeliensis, Myrtus communisandPistacia lentiscusis to be noticed. This bush is either compact or rarefied so that it makes a sort of « garigue » on limestone withEuphorbia dendroides, Helichrysum stoechas, Ruta chalepensis, Thymus vulgaris. Owing to the fact that some land strips of Palmaria escaped from fire a thermophilous vegetation is to be found, with a few trees ofPinus halepensisand with a thick undergrowth ofEuphorbia dendroides, Cistus incanus, Pistacia lentiscus, Myrtus communis, Smilax aspera. The vegetation of the northern side of Palmaria and Tino is less thermophilous, together with a thick wood ofQuercus ilexwith some plants ofQuercus pubescensand with undergrowth ofViburnum tinus, Smilax aspera, Smilax mauritanica, Coronilla emerus; this wood, especially in the higher part of Palmaria, shows some glades whereErica arborea, Cistus salvifolius, Dorycnium hirsutumgrow, with some entities which are distributed quite far from the sea, such asPeucedanum cervaria. Still on the northern side of Palmaria there are some traces of chestnut woods withCastanea sativa, Quercus pubescens, Ostrya carpinifolia, Corylus avellana, Cytisus laburnumand with some plants that usually grow in the cooler areas among the chestnut woods and often in the beech woods likeDaphne laureola, Digitalis lutea, Helleborus foetidusandSesleria autumnalis. A comparison between the biological spectrum of the two islands with the one of Capo Caccia in north western Sardinia and of Marettimo island in western Sicily, clearly shows that in going down southwards, a strong increase of the therophytes (respectively 29,57%, 41,73%, 49,59%), of the chamaephytes and of the nanophanerophytes (13,53%, 16,94%, 18,47%) is to be noticed, while the hemicryptophytes decrease (35,33%, 22,72%, 21,28%). Besides, the vegetation of Capo Caccia although being situated half way between the two Ligurian islands and Marettimo, is much more similar to the latter one; evidently Palmaria and Tino are conditioned by their closeness to the La Spezia coasts while having a climate quite different from them.

ISSN:0017-0070    

DOI:10.1080/11263507209426540

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Cytotaxonomical studies in Euphorbiaceae: Euphorbia angulata Jacq. and E. dulcis L. — E. dulcisandE. angulatacan be easily distinguished by the following key:

ISSN:0017-0070    

DOI:10.1080/11263507209426541

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

Dormancy and salt-tolerance in two spontaneous species of Hordeum. — Dormancy behaviour and germination capacity in salt-solutions ofHordeum murinumL. andHordeum marinumHuds. seeds have been studied. Seeds (caryopses) have been sown in Petri dishes on filter paper soaked with deionized water (control) or with NaCl solutions at concentrations: 3.2 - 6.5 - 13.0 - 26.0%. Germination was tested during after-ripening, 20, 40, 60, 100, 160, 260 and 365 days from harvest (fully ripe seeds). The two species ofHordeumare spontaneous and characterized by peculiar ecological features. The present results have shown that, during the first year from harvest,Hordeum murinumandH. marinumhave different length and strength of dormancy (longer and stronger inH. marinumthan inH. murinum). Germination capacity and energy of the two species — during after-ripening stage — when seeds are sown in salt-solutions differ strongly and seem to be correlated with dormancy.Hordeum murinumseeds, which exhibit a dormancy shorter than those ofH. marinum, germinate earlier when sown on salt-solutions. Besides, germination energy ofH. murinumseeds is, in all assayed solutions, during 260 days from ripening, significantly higher than the one ofH. marinum. This species, sown in NaCl solution at concentration 26%, shows a reduced germination capacity. Germination behaviour of the twoHordeumspecies does not seem to agree with their ecological features as shown byH. marinum. This is present in halophilic associations of coast shores and shows a higher salt-tolerance thanH. murinum.

ISSN:0017-0070    

DOI:10.1080/11263507209426542

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue

ISSN:0017-0070    

DOI:10.1080/11263507209426539

出版商:Taylor & Francis Group    

年代:1972

数据来源: Taylor