8 TRANS. ST. LOUIS ACAD. SCIENCE. 



Out representatives of the Order Linace(^ belong to the tribe 

 Eulinece of Planchon and Bentham & Hooker, so that for our 

 purpose, aside from all consideration of the doubtful propriety of 

 including Erythroxylcce^ &c., in the Order, the ordinal charac- 

 ters may be limited to those which characterize this tribe, which 

 includes, in addition to Linum, on\y the small genera Radiola, of 

 a single species, characterized by its 4-merous flowers, and Rein- 

 Tvardiia, with a few shrubby species which resemble our Hes- 

 perolinons in having 5-merous flowers, rendered unsymmetrical 

 by a reduction in the number of carpels, and (?) appendaged 

 petals.* 



In a study of Hesferolinon considerable assistance is appa- 

 rently to be obtained from the appendages of the petals (PI. IV.), 

 which represent delicate, more or less crenate or lacerate scales 

 across the inner or ventral face of the claw, and correspond in 

 position to a hairy line well developed on the unappendaged 

 petals of L. Bei-landieri and related species of Linastrutn (PI. 

 IV. fig. 12). I shall be glad to learn from those who have the 

 opportunity to observe these Californian plants in the field, how 

 constant the appendages prove to be. 



The form and dehiscence of the capsule ofler some of the most 

 evident characters in studying the genus as a whole, and, so far 

 as I have been able to learn, these are quite constant. Dr. En- 

 gelmann has indicated that the capsules of the rigidtim group 

 are provided with a series of curious dark brown cartilaginous 

 insertions (PI. III. fig. 7-1 1), which are situated at the base of the 

 partitions between the carpels (not opposite the false septa, as he 

 states, apparently by a slip of the pen). While the capsule usually 

 splits into twice as many valves or cocci as there are carpels, in 

 these species, as Engelmann has shown, the number of valves is 

 equal to that of the carpels, but each consists of the halves of two 

 carpels, the primary dehiscence of the capsule occurring through 

 the false septa. 



An interesting biological consideration in a comprehensive 

 study of Linaceas is that relating to the homogony or heterogony 

 of their flowers ; but, as the New World species are exclusively 



* On Reinwardtia see Urban : Verhandl. Bot. Verein, Prov. Brandenburg, i8Si, xxii. 

 iS-aj; Abstracts in Just's Bot. Jahresb. vii. (i), 130; viii. (a), 123. 



