Nondestructive approach of modeling leaf area could be useful for plant growth estimation especially when number of available plants is limited and/or experiment demands repeated estimation of leaf area over a time scale. A total of 1,280 leaves were selected randomly from eight different morphotypes of som (Persea bombycina) established at randomized complete block design under recommended cultural regimes in field. Maximum leaf laminar width (B), length (L) and their squares B2, L2; leaf area (LA), and lamina length × width (L×B) were determined over two successive seasons. Leaf parameters were significantly affected by morphotypes; but seasons had nonsignificant impacts on tested features. Therefore, pooled seasonal morphotype means of each parameter were used to establish relationship with LA. L and its square L2 did not provide accurate models for LA predictions. Considerably better models were obtained by using B (y = 2.984 + 7.9664 x, R2 = 0.615, P≥0.001, n = 119) and B2 (y = 12.784+ 0.9604 x, R2 = 0.605, P≥0.001, n = 119) as independent variables. However, maximum accuracy of prediction of LA could be achieved through a simple linear relationship of L×B (y = 8.2203 + 0.4224 x, R2 = 0.843, P≥0.0001, n = 119). The model (LA:L×B) was validated with randomly selected leaf samples (n = 360) of som morphotypes and highly significant (P≤0.001) linear function was found between actual and predicted LAs. Therefore, the last model may consider adequate to predict leaf area of all cultivars of som with sufficient fidelity. and S. Chattopadhyay ... [et al.].
Sklenobýl bezlistý (Epipogium aphyllum) patří mezi nejvzácnější druhy naší flóry. Roste v bučinách a jehličnatých lesích s humózní půdou, často na lesních prameništích. Ještě donedávna byl v Čechách hodnocen jako nezvěstný. V r. 2006 se ale podařilo objevit několik malých lokalit na Šumavském Boubíně, poté v r. 2008 i jedna lokalita v Krkonoších. V červnu r. 2013 v náplavech Jizery a hned u cesty nedaleko Kořenova se podařilo objevit další dvě mikrolokality tohoto ohroženého druhu. Bylo by velmi povzbuzující domnívat se, že nárůst počtu lokalit nejen sklenobýlu, ale i jiných ohrožených druhů indikuje zlepšující se stav prostředí., Epipogium aphyllum is one of the rarest plant species of the Czech flora. It grows in humus-rich soil in beech and spruce forests, often in the vicinity of forest springs. The species has been considered missing in Bohemia until recent discoveries of a few sites in Boubín in the Šumava Mts. (Bohemian Forest, 2006) and in the Krkonoše Mts. (Giant Mts., 2008). Two new populations were found in the Giant Mts. in June 2013 - in alluvial deposits of the Jizera river and along the forest road close to the Kořenov village., and Pavla Čížková, Kamila Lencová, Pavel Hubený.
Článek se věnuje nově popsanému rodu Oreojuncus Záveská Drábková et Kirschner, který zahrnuje dva druhy - Oreojuncus trifidus a Oreojuncus monanthos. V České republice se vyskytuje pouze O. trifidus, sítina horská trojklanná, které je věnována větší pozornost. Rod Oreojuncus byl tradičně zařazován mezi sítiny (Juncus) sekce Steirochloa, avšak na základě komplexního výzkumu zahrnujícího fylogenetickou analýzu molekulárních dat a revizi morfologie byl vyčleněn jako samostatný, osmý rod čeledi sítinovitých (Juncaceae)., The new genus Oreojuncus Záveská Drábková et Kirschner has been described, with two species - O. trifidus and O. monanthos. Attention is given to the first species, which occurs in the Czech Republic. The genus Oreojuncus has been traditionally included in the Juncus sect. Steirochloa; however, complex research based on phylogenetic analysis of the molecular data and morphological revision revealed the necessity to establish this eighth genus in the Juncaceae family., and Lenka Záveská Drábková.