HIGHER SUBDIVISIONS. 



19 



equal rank 

 character. 



Th 



question is which of th 



And the answer seems clear; phyllota 



two is to be abandoned as the primary 



in future 



of artificial keys to species, must take a subordinate position 

 are the following. In the first place 



in the for 

 The reasons for thi 



view 



the proportion of beaked to beakle 



Corollas beaked 



• • ■ 



• • • 



» 



without beaks ... 



% • » 



• • • 



49-4 per cent, of the whole, 



• • • 



■ • • 



50 6 



n 



» 



shows that this character, while quite as natural 



the 



much mor 



evenly 



Ag 



both the beaked and beakle 



phyllotaxic one, d 



vides the genus 



divided by floral characters, wh 



a primary di\ 



divisions may be furt] 



b 



to nothing beyond. Finally, a subdivision based 



throw light on the developmental history of the genus: one based on habit cannot do 



>n by phyllotaxis once effected leads 

 on floral structure may be hoped to 



or can only do so indirectly 



At first sight it would 

 of subdividing the genus must be into 



appear that the most natural as well as most 



pie method 



groups wherein the corolla is beaked 



(2) 



)» 



» 



V 



not beaked 



But the occurrence of groups that are in the highest degree and in the most obviou 



manner natural, such as the Acaules, Recutita;, Carnosce. Tristes 



i 



d many more, which 



cond 



theless within their particular limits exhibit a transition from a beakless to a beaked 

 tion as complete as that shown by the genus as a whole, makes the recognition < 



of 

 By recognising this we obtain three 

 divisions, clearly not quite natural in their limits, and therefore not deserving to be called 



an intermediate subd 



absolutely necessary 



sub-genera, but apparently in accordance with the genealogical arrangement 



f the 



groups, and so possessing the advantage of being c; 



so as to pass progressively from the more to the less specialised groups, these 



pable of a serial disposition. Arranged 



Division I. — LONGIROSTRES ; — Corolla tube straight, slender, uniform ; lip large, sessile, 



more delicate in texture than the firm, long-beaked hood. 



ADUNOE; — Corolla tube curved, cylindric, slightly enlarged towards 



II. 



the top; lip sessile 

 beaked or beakless hood. 



or stipitate, more delicate 



in texture than the 



III. 



EROSTRES ; 



Corolla tube infract, infundibuliform ; lip 



stipitate, base 



erect 2-cristate above, lobes patent of same texture as beakless 



hood. 



But this 



natural disposition that 



gement, while it accords with facts of structure, implies a simplicity of 



study of these facts dispels 



Thus the division LONGIROSTBES contains two highly natural sections 



SlPHONANTlLE 



olla tube usually much elongated ; filaments inserted between 



middle and top of tube 



d 



ally 



ust below the apex 



beak 



in 



bud 



circinnate, with dorsal aspect apposed to median line of lip and apex 

 directed to throat of corolla. 



« 



Ann. Roy. Bot. Gaed. Calcutta, Vol. Ill 



