786 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Dendrobium regium. By R. A. Rolfe (Orch. Rev. vol. xii. p. 228). 

 Description of this new Dendrobium, from a plant flowered at Kew, and 

 other interesting items are afforded. — H. J. C. 



Dendrobium Williamsoni. By AY. B. H. {Bop. Mag. t. 7974).— 

 Native of North-East India. Nat. ord. Orchidacece ; tribe Epidendrea. 

 Caulescent, stems 6 to 12 inches. Leaves oblong-lanceolate. Flowers 

 2 to 3 inches across, ivory-white ; lateral lobes of the lip tinged with 

 yellow, having a zone of bright orange-red ; lip bearded.— G. H. 



Derbesia, On the Cell-contents of. By A. Ernst (Flora, xciii. 

 1904, pp. 514-532 ; t. xxii.). — The chloroplasts resemble those of Bryopsis ; 

 they are spindled-shaped, often curved, with 1-3 pyrenoids, which are, 

 however, absent from the smaller ones. Starch formation takes place 

 even in the absence of pyrenoids, which are, indeed, never present in 

 D. neglecta. Formed proteids occur in the form of threads (fluorescing 

 bluish-green), spherulites, and isometric octahedral crystals. Calcium 

 oxalate occurs in D. tenuissima in square prisms, tetragonal pyramids, 

 or combinations of the two. — M. H. 



Dianthus call-alpinus. Anon. (Gard. Mag. 2643, p. 408 ; 25/6/04). 



A good illustration of this beautiful hybrid Rock Pink raised between 

 D. callizonus and D. alpinus. It combines the characters of both 

 parents, both in growth and flowers, which are 1^ inch across ; bright 

 pink with a crimson zone. — W. G. 



Dicentra chrysantha. By W. B. H. (Bot. Mag. t. 7954).— Native 

 of California. Nat. ord. Fumarictcece. A perennial glabrous herb with 

 dissected leaves and golden-yellow flowers. — G. H. 



Dietyotaceae, Studies in the. I. The Cytology of the Tetra- 

 sporangium and the Germinating- Tetraspore. By J. Lloyd 



Williams (Ann. Hot. xviii. Jan. 1904, pp. 141-160; 2 plates). — An alter- 

 nation of generations is established for this alga. The first division of the 

 tetraspore mother-cell is a reduction division, the chromosomes being 

 reduced to sixteen in number, and the earlier mitoses of the young plant 

 produced from the tetraspore show the reduced number. The male and 

 female plants have sixteen chromosomes, and the tetrasporic plants have 

 thirty-two, up to, and including, the stalk cell division of the tetraspore. 



A. D. C. 



Dietyotaceae, Studies in the. II. The Cytology of the Gameto- 



phyte Generation. By J. Lloyd Williams (A nn. Bot. xviii. April 1904, 

 pp. 1H3-202 ; 3 plates). — The development of the oogonia and antheridia 

 was investigated, and also the processes of fertilisation and germination 

 of the egg. Parthenogenesis was found occasionally to occur. The 

 sexual cells are produced simultaneously in fortnightly crops, the eggs 

 reaching maturity at each spring tide, llemarkable periodicity of this 

 nature has not hitherto been observed in Alga. — A. D. C. 



Digitalis ferruginea, Abnormal Flowers of. By FriBdrich 

 Hildebrand [Beih. Hot. Cent. xvi. pp. 847-366; 2 plates). —Gives a 



