REDUCTION OF SPONGIOSYNDESMUS GILLI TO LADYGINIA LIPSKY (UMBELLIFERAE)

Comparative morphological and carpological investigation shows that Ladyginia and Spongiosyndesmus are congeneric. An emended generic description of Ladyginia is given and two new nomenclature! combinations Ladyginia afghanica and L. gigantea are made.


INTRODUCTION
Spongiosyndesmus Gilli is one of the genera of Umbelliferae endemic in the 'Flora Iranica' area. There are two known species, the type species S. afghanicus Gilli, described simultaneously with the genus (Gilli, 1959) and S. giganteus described by Leute during preliminary studies for the treatment of the Umbelliferae for Flora Iranica (Leute, 1972).
A detailed description was given of this genus particularly in regard to the carpology. The structure of the fruits of S. afghanicus, as described by Gilli, seems to be distinctive. The fruit is compressed dorsally and thus the taxon belongs to the tribe Peucedaneae. However, the mature fruit is devoid of vallecular and commissural secretory ducts, although it is probable that vittae do exist when the fruit is immature. The mencarps of 5. afghanicus have a peculiar commissural surface, spongiose, rough, rugose or lacerate, from which Gilli derived the name for his new genus.
The peculiar structure of the mericarp secretory system described by Gilli is, we believe, the most interesting aspect of the genus. A lack of vallecular and commissural ducts is known for some Apioideae (e.g. Aegopodium L., Conium L., Silaum Miller) but it is rather rare and sporadic. It seems usual to regard this as a generic character indicative of considerable specialization; this character is especially rare in the so-called flatfruited Umbelliferae. The absence of vallecular vittae is observed for instance in the genus Johrenia DC, but its species have very large costal ducts with a spongiose inflated pericarp. In his original description, Gilli compared Spongiosyndesmus with Pastinacopsis Golosk. While indeed the latter has dorsally compressed fruit without vittae in either the valleculae or on the commissure, it is a rather superfluous analogy because P. glacialis has a pericarp structure completely typical for members of the tribe Tordylieae. One of the marked differences between Tordylieae and the taxa closely related to Ferula (Peucedaneae) seems to be the presence in Tordylieae of vertically orientated fibres in the hypendocarp or sclerocarp (the inner part of the mesocarp made up of Hgnified prosenchyma of horizontally or vertically orientated cells with rounded or oval pores); they are absent in Peucedaneae.

DISCUSSION
Authentic specimens of Spongiosyndesmus were not to be found in herbaria in the USSR. Therefore critical study of this genus only became possible when duplicates of the Umbelliferae collected in Afghanistan, in particular by I. Hedge and by J. Lamond, were received from RBG Edinburgh. Since then an opportunity has arisen to study these collections in situ at Edinburghthereby widening the amount of herbarium material studied of both species of Spongiosyndesmus.
Amongst this material we found one specimen of S. afghanicus with quite mature fruit (Prov. Qataghan: lower Andarab valley, 14km E of the village, 1100m, serpentine slope, 'Fl. yellow. Plant up to 4-5 ft', 1 vii 1965, J. Lamond 2289). This specimen is not cited in Flora Iranica but matches the photograph of an authentic sheet (Rechinger 1987, t.422) and was in fact collected at the same time. Our examination of herbarium material and of the anatomical structure of the fruit confirms the attribution of the taxon to Peucedaneae. The fruit has a welldeveloped layer of hypendocarp which indicates that Spongiosyndesmus belongs to Drude's subtribe Ferulinae. The analysis of all the characters -both exomorphological (form of the umbels, leaves and stems) and carpological -bears witness to the great affinity between Spongiosyndesmus and the genus Ladyginia.
This genus was described by Lipsky (1904: 150), reduced to synonymy under Ferula by Koso-Poljansky (1916: 111), and restored again in Flora URSS (Schischkin, 1951: 143). Our investigation (Pimenov & Kirillina, 1980) showed, however, a great similarity of fruit structure between the only known species of this genus, L. bucharica, and Ferula species, although it must be admitted that we had overestimated the value of hypendocarp presence in the fruit of both taxa -Ladyginia and Ferula. This character does not seem to be an absolute criterion of generic limits in the Umbelliferae, though neither do any other characters! Moreover, species with rather reduced hypendocarp ai£ known in various infrageneric taxa of Ferula, in particular in the subgenera Peucedanoides (Safina & Pimenov, 1983) and Ferula (Safina & Pimenov, 1990).
The genus Ladyginia is upheld in both Flora of Tadzhikistan (Korovin et al., 1984: 196) and in Flora Iranica (Rechinger, 1987: 427). Now we also accept this genus with its type species L. bucharica as separate from Ferula, based on more than just carpological characters, and taking into account the result of the immunochemical investigation of storage proteins in the seeds of Ladyginia and Ferula (Shneyer et al., 1991).
L. bucharica is a widely distributed species in South Uzbekistan and South Tadzhikistan (formerly 'the mountainous Bukhara') and it would be strange if it were not fairly common in the adjacent regions of Afghanistan. True, Flora Iranica indicates only two localities for the species in Afghanistan, although one of them may belong elsewhere to judge from a photograph (Rechinger, 1987, t. 385). However, another trustworthy specimen (Prov. Takhar: between Talicfan and Qeshm, steep slopes of gorge, 29 vi 1969. /. Hedge & P. Wendelbo 9262) has been received from E, but is not cited in Flora Iranica.
Obviously it was necessary to compare Ladyginia and Spongiosyndesmus on the basis of all essential taxonomic characters including the peculiarities of the pericarp, which seem to be significant for the taxonomy of this group of the Umbelliferae. This  comparison has revealed an affinity in many important features: the fruits of both taxa investigated are very much compressed dorsally, and have a large commissure with rather distinctive spongiose surface (this character has been regarded as a key character for Spongiosyndesmus but passed unnoticed in Ladyginia), a well-developed hypendocarp (this feature on the contrary, has been described for Ladyginia but has not been noted for Spongiosyndesmus) -see Figs 1 & 2. Certainly, the fruits of L. bucharica (15-18 x 9-10mm) and S. afghanicus (5-6.5 x 3.5-4mm) differ considerably in sizebut the size of fruit of the other species of Spongiosyndesmus -S. giganteus -occupies rather an intermediate position. Besides the carpology, the two genera are rather similar in their life-form (both are perennials), in the stem structure (the stems are rather thin, solid, virgate, without ribs), leaf sheaths (narrow, lanceolate), terminal leaf lobes (rather large, especially those of L. bucharica and S. giganteus), and the inflorescence structure (terminal umbels only, in contrast to most Ferula species which possess both terminal and lateral umbels). Thus, we have not revealed any essential differences between these two genera. The specific differences detected are within the range of variation usual for rather small genera of the Umbelliferae (height of the plant, size of terminal leaf lobes, size of mericarps). As a result we propose to unite these genera under the earlier name Ladyginia; an enlarged more exact generic description as well as two new nomenclatural combinations for species of the former Spongiosyndesmus are necessary and a key to the species is given. ActaHortiPetrop. 23:150 (1904) -SpongiosyndesmusGilli,Feddes Repert. 61: 199 (1959, syn. nov. Plantae perennes, polycarpicae, radicibus palaribus incrassatis ramosis. Folia radicalia biternata lobis terminalibus latis, integris vel vix lobatis, margine crenatis vel dentatis vel plus minusve profunde dissectis. Folia caulina vaginis oblongo-lanceolatis longis