i go Gibbs . — Bio-histological notes on some new 
of which the aerial shoots arise from a bifurcation of the rhizome. The 
branching is sympodial, and several aerial stems are given off in one season, 
both flowering and vegetative (PI. XI, Fig. i). The rhizome consists of a 
solid central cylinder (PI. XII, Fig. 8) composed of many fibro-vascular 
bundles embedded in fundamental tissue: it is bounded by an endodermis 
accompanied by several layers of sclerotic cells (Fig. 8, e. sch.). A very 
broad cortex of unmodified parenchyma succeeds the endodermis and the 
sclerotic zone. Of this the peripheral portion is composed of larger cells, 
is not aerenchymatous, and is reinforced by hypodermal ribs and small 
isolated groups of more centrally placed sclerotic tissue (Fig. 8, sch). 
The epidermis is slightly circularized, and tannin is abundant through the 
rhizome where starch occurs in the cortex, but not in the central cylinder. 
The cortex in the Cyperaceae, according to Plowman is highly susceptible 
to environment and varies in the same species. Duval-Jouve 2 observes 
that in hot and damp localities in Algeria the cortical zone is soon destroyed, 
but persists longer in dry and sweet (‘ frais ’) places. He mentions this fact 
against Guillard’s 3 theory that the size of the cortical envelope of roots and 
rhizomes depends on the humidity of the soil and not on a special organiza- 
tion. The present case would seem to support the latter author. 
In the centra] cylinder the fibro-vascular bundles come under Plow- 
man’s 1 ‘ amphivasal ’ type, the bundles being concentric with the xylem 
distributed round the phloem (PL XII, Fig. 8, a.v.b). The bundles are 
very numerous, especially near the periphery of the central cylinder. The 
central strands are larger, characterized by a large centripetal mass of scler- 
enchyma showing protoxylem lacunae. The section Plowman 1 describes 
and figures for Scirpus cyperinus Kunth might pass for Fuirena Oedipus , 
with the exception of the sclerotic ring round the endodermis, which, accord- 
ing to him, is characteristic of Fuirena . 
Aerial stem. In this species the stem is quadrangular, as is also the 
case in F. umbellata Rottb., 4 but otherwise this seems to be a very uncommon 
feature in the Cyperaceae, in which the stems are usually round or tri- 
angular. The first three or four internodes of the stem are very short 
and covered by membranous scale leaves, light brown in colour. A cross 
section through the third internode from the rhizome shows a typical 
hygrophilous structure (PI. XII, Fig. n) with large medullary air-spaces 
of schizogenous origin, separated by delicate plates of parenchyma which 
accompany the medullary bundles. The cortical bundles are arranged 
1 Plowman, Comparative Anatomy and Phylogeny of the Cyperaceae (Annals of Botany, xx, 
1906, pp. 1-33, Pis. I-XI). 
2 Duval-Jouve, Etude histotaxique des Cyperus de France (Memoires de l’Acad. des Sci. et 
des Lett, de Montpellier, viii, 1874, pp. 347-412, Pis. XTX-XXII). 
3 Guillard, Bull. Soc. Bot. de France, xvi. 420. 
4 Rickli, Beitrage zur vergl. Anat. d. Cyperaceen, m. besonderer Beriicksichtigung d. inneren 
Parenchymscheide (Pringsh. Jahrb. f. wiss. Bot., xxvii, 1895, pp. 4S5-580, Pis. XVIII-XIX). 
