BRYOPSIS. 



[ 122 ] 



BUDS. 



thorax ; abdominal margin studded with 

 short, somewhat triangular sparse papillae. 

 B. speciosa. 



BIBL. Koch, Uebersicht, 61; Murray, 

 EC. Ent. 117. 



BRYOP'SIS, Lamouroux. A marine 

 genus of Siphoneae (Confervoid Algae), of 

 which the British species form beautiful 

 green, somewhat elastic, feathered silky 

 tufts, from 1 to 4" high upon rocks or upon 

 other Algae, in tide-pools. The whole axis 

 and proper branches of each plant consist of 

 one large ramified cell, the cavity being 

 continuous throughout, the membranous 

 wall rather thick, and somewhat gela- 

 tinous externally ; the branches are naked 

 below, but clothed above by small ramuli, 

 arranged like leaves, distichously, spirally, 

 or irregularly. The main axes and branches 

 grow indefinitely by development of the 

 apices; the ramuli are limited in their 

 development, and they are ultimately shut 

 off by septa, at last falling off by the cir- 

 cular rupture of their wall, just above their 

 point of origin. 



When examined early, the ramuli are 

 found to have their walls lined with largish 

 elliptical green grains, each of which has at 

 first a round light central body, colourable 

 blue by iodine when fully formed (starch- 

 corpuscle). The branches exhibit the phe- 

 nomenon of reproduction, in irregular order, 

 in the following way. The green bodies on 

 their walls multiply by subdivision, and 

 increase in size and number until they com- 

 pletely fill the tubular cavity of the ramule, 

 pressing upon one another so as to form a 

 compound dark-green mass. A peculiar 

 swarming movement is next observed in 

 the green bodies, which increases more and 

 more; and, the parent tube opening by a pore 

 near its apex, the green bodies escape as 

 elongated pear-shaped zoospores or active 

 gonidia with cilia, according to Thuret, 

 two and four in B. hypnoides, only two in 

 B. plumosa. The successive emission of 

 the gonidia from the various tubes of one 

 plant occupies several days. 



After the gonidia have come to rest, they 

 acquire a spherical form, and gradually in- 

 crease in size ; at the end of a month or six 

 weeks their diameter is twice or thrice the 

 original dimensions ; and then they begin to 

 elongate into a tube similar to the parent. 

 Agardh found them elongate, either in one 

 direction or in two, at first ; but one end 

 soon swelled into a thickened organ of 

 attachment, while the other began about 



spe- 



the sixth week to branch. British 

 cies : 



B. plumosa, Huds. (PI. 4. fig. 19). Deep 

 green, 1 to 4 inches high, more or less 

 branched ; the branches pinnated with sub- 

 opposite distichous or rarely irregular ra- 

 mules. Harvey ,Afar. Alga, 2nd ed. pi. 24 B ; 

 Phycol. Brit. pi. 3 ; Greville, Alga, pi. 19 j 

 Engl. Bot. (Ulva plumosa), 2375. 



B. hypnoides, Lamour. Yellow-green, 



2 to 4 inches high, more slender and more 

 branched, branches repeatedly divided, ra- 

 mules irregularly scattered, somewhat pin- 

 nate, more or less dense. Harvey, Phyc. 

 Brit. pi. 119. 



BIBL. Systematic, as above, and Kiitzing, 

 Sp. Alg. p. 490 ; Physiology, &c., Agardh, 

 Ann. d. Sc. Nat. 2 s<5r. vi. 200, pi. 12; Na- 

 geli, Zeits. iviss. Bot. 1844-46 (Ray Soc. 

 1845, 269, pi. 6. figs. 11, 12; 1849, 97, pi. 2. 

 figs. 1-3) ; Neu. Algen-Systeme, 1847, 171, 

 pi. 1. figs. 44-56 ; Thuret, Ann. d. Sc. N. 



3 se>. xiv. 8, pi. 16. figs. 1-6 ; Braun, Verj. 

 137 (Eay Soc. 1853, p. 120) ; Pringsheim, 

 Monatsber Berl. Akad. 1871 ; Sachs, Bot. 

 275. 



BRYOZO'A. See POLYZOA. 



BRY'UM, Dill. A genus of operculate 

 Mosses, usually acrocarpous, containing a 

 large number of British species, even in its 

 restricted condition. 



Among the most common of these are 

 B. nutans (fig. 467), cernuum, intermedium, 

 capillare, caspiticium, &c. Many of the 

 older species are now included under 

 MNIUM. 



BIBL. Wilson, Bryol. Brit. p. 221. 



BUC'CJNUM, L. B. undulatum, the 

 common Whelk. The tongue forms an 

 interesting microscopic object. 



BUDS. The buds of plants form inter- 

 esting objects of microscopic investigation 

 on many accounts, first, in tracing the de- 

 velopment of the organs, and also of the 

 tissues of which these are formed; secondly, 

 on account of certain temporary structures 

 which they exhibit. The thick epidermis 

 of the scales of the winter-buds of ordinary 

 trees, as of the ash, &c., is a very favour- 

 able object for sections to show the charac- 

 ter of this tissue when highly developed. 

 The internal soft scales and young leaves of 

 very many of these winter-buds, as well as 

 other buds of herbaceous plants, are clothed 

 with glandular hairs, which disappear when 

 the buds are expanded ; and these often 

 afford advantageous material for studying 

 cell-development. See GEMMAE. 



