218 Fr. J. Mathiesen. 



orne (polystely and a "réseau radicifère"); polystely could 

 not be proved in the case of Dodecatheon frigidum. These 

 anomalies have already been thoroughly described by van 

 Tieghem 1 and others for Pr. nivalis, Pr. stricta, Pr. sibirica 

 and Pr. farin. Stone-cells, single or in small groups, are 

 present in the medulla of Pr. sibirica and Pr. stricta, and 

 the latter also has them enclosed in the individual steles. 

 The cells of the ground-tissue are parenchymatic, coarsely 

 pitted and contain starch. Dodecatheon frigidum has an active 

 cork-cambium in the subepidermal layer of the cortex. 



III. The vascular bundles of the peduncle and flower 

 stalks are arranged in a regular circle. In most of the species 

 they are surrounded by a sclerenchymatic ring (especi- 

 ally strong in Androsaces sept.) ; Pr. nivalis seems however 

 to lack this stereome. A parenchymatic tissue is present 

 outside the stereome; it consists of axially extended cells 

 with large intercellular spaces, and is rich in chlorophyll 

 granules. The epidermis is provided with stomates and 

 covered with hairs of the same type as those present on 

 the leaves of the respective species. The central ground- 

 tissue consists of thin-walled cells, and is always homo- 

 geneous. 



IV. The leaves of the Primula species, and those of 

 Dodecatheon frigidum are provided on both surfaces, with 

 glandular hairs of the usual Primula type (a unicellular head 

 on a one-celled stalk). Androsaces sept, has in addition hairs 

 with two-celled stalks, while in Androsaces chamaejasme the 

 head of the glandular hairs may also be two-celled, the division 

 being always effected by a central vertical wall. 



The dense mealy covering, so characteristic for the 



1 van Tieghem: Struct, de la tige d. Primevères & Groupement d. 

 Primevères, etc.; Bull. Soc. bot. de France, 1886. van Tieghem et 

 Douliot: Polystélie; Ann. se. nat. Ser. 7, T. III, 1886. For the 

 literature of this subject see also Solereder: System. Anat. der 

 Dicotyl.; Stuttgart, 1899. 



