212 CXVIII. THYMEL^ACEyE (pEARSON). 



Order CXVIII. THYMEL^ACE^. (By H. H. W. Pearson.) 



Flowers perigynous, regular, dichlamydeous or with the petals 

 aborted, hermaphrodite* or, by abortion, polygamous or dicEcious. 

 Calyx tubular, cylindric or square in section, usually somewhat swollen 

 around the ovary ; lobes 4 or 5, imbricate, spreading during flowering, 

 equal or rarely with the 2 interior rather smaller. Petals equal to and 

 alternating with the calyx- lobes, inserted on the throat of the tube or 

 below the stamens, usually much smaller than the calyx-lobes, fre- 

 quently 0. Stamens as many or twice as many as the calyx-lobes, 

 inserted on the calyx-tube — if in two whorls those of the upper 

 usually opposite to the calyx-lobes ; filaments usually very short ; 

 anthers 2-celled, introrse, dehiscing by parallel longitudinal slits. Disc 

 hypogynous, annular, cup-shaped, lobed or 0. Ovary superior, 1- or 2- 

 celled (4-celled in Octolejns)^ sessile or shortly stalked, entire. Style 

 slender, short or long, excentric (1-celled ovary) or central (2-celled 

 ovary) ; stigma terminal, capitate or subdiscoid. Ovule 1 in each cell, 

 affixed laterally near the apex, anatropous, pendulous, with a ventral 

 raphe. Fruit a nut, drupe, or pyrene (capsule in Octolepis), usually 

 enclosed in the base of the calyx-tube. Albumen of the seed fleshy, 

 copious, scanty or 0. Embryo straight ; cotyledons fleshy, usually 

 thick. — Trees or shrubs, very rarely slander annual herbs, with tough 

 fibrous bark. Leaves opposite, alternate or scattered, entire, small 

 ericoid or large, flat. Stipules 0. Flowers in involucrate heads, or 

 in short racemes, spikes or fascicles, rarely solitary ; the heads or 

 spikes at the apices of the branches or sessile (rarely pedunculate) in the 

 leaf-axils. Bracts various, frequently few or absent. 



About -iOO species: many in South Africa, ihe Mediterranean region and 

 Australia ; a few in Asia and North and South America. About 90 species in 

 Tropienl Africa. 



I have not followed Oilg in the reduction of the genera Arthrosolen and 

 Lasiosiphon to Gnidia. Lasiosiphon is distinguished not only by its 5-merous 

 flower, but also by other characters readily recognisied in the field. Arthrosolen 

 presents some difficulty. The only constant cli!ir;icter which separates it from 

 Onidia is the absence of petals. These are very minute in some species of Gnidia, 

 and, on this account as well as for other reasons, these genera must be regarded as 

 closely allied. But several of the genera of the ThymelaacecB, as of many other 

 families, are necessarily separated by small and apparently artificial chaiacters, and 

 it is doubtful whether any useful purpose is served by attempting to raise the 

 standard of generic differences at the cost of a further complication of synonymy. 



The material of Octolepis at Kew is too incomplete to allow of iiide[)endent 

 investigation, and I have therefore followed Oliver and Gilg in retaining it within 

 this familv, witli which it undoubtedly possesses some degree of affinity. 



Teibe 1. Sutbymelaeae. Ovary 1-celled. Ovule solitary. Fruit a nut. 



Stamens as many as the calyx-lobes . . .1. SteuTHIOLA. 



Stamens twice as many as the calyx-lobes, inserted 

 above the middle of the calyx-tube. 

 Flowers in bracteate heads or s])ikes, rarely axillary. 

 Petals u: shorter than the calyx-lobes. 



